This Study aims to testing the effect of using Gagne Model and Klausmeire' Model and the effect of the previous a Chievement level. In addition, it tests the Interaction between the teaching Method and the previous a Chievement level on first Preparatory Ptudent' acquisition of the Geographic Concepts. To accomplish these aims, the Study attempts to answer the following three questions: 1. Does the change in the used teaching Method (Gagne' Model and Klausmeire' Model) affect first Preparatory Student acquisition of some The Geographic Concepts? 2. Does the difference in the previous a Chievement level change the first Preparatory Student acquisition of some Geographic Concepts? 3. Is there any Interaction between the previous a Chievement level and the used teaching Method in first Preparatory Student acquisition of The Geographic Concepts? The sample of the Study was restricted to 142 first Preparatory Student Studying at government Schools in the interior region Sultanate of Oman during the first Semester 1998/1999. They were distributed randomly on Four Classes in Two Schools and were chosen randomly . The Two Models had been taught in each school and the Models were distributed by the random Assignment on the selected sections. Then each section was divided into Three subgroups according to the previous aChievement level (high, medium, low) and based on their grades in the Social Study Course in the former semester of the Study. To answer the questions of the Study and verify its Hypothesis, the Study relied on several research Procedures in which the researcher prepared daily Study plans for the Concepts selected from the Unit: Water and Air from The Social Studies Course. These Concepts are the terrestrial system, The Atmosphere, The Hydrosphere, The Biosphere , The Geosphere (Crust of the Earth), Waterways, Oceans, Seas, Canals, Straits. The researcher followed the steps mentioned in Gagne inductive Model and Klausmeier deductive Model. He also prepared an a Chievement test that consisted of 40 multiple choice items to measure aChievement of Student' acquisition of the Geographic Concepts generated from Bloom's lower cognitive domain (knowledge, Comprehension, Application). The validity of the daily Study plans, which were prepared for teaching the selected Concepts and the achievement test, was verified. This was done through handing them over to a group of specialized expents in the Curriculum and Methodology of Social Studies and some Geography Teachers. The researcher, then, had applied many of the expents' modifications and suggestions until each of the daily Study plans and the a Chievement test becomes in their final applicable version. After that, the test was given to the Student as a Pre Test to check the equivalence of the Two groups and then as a Post Test to answer the questions of the Study. The reliability of the test was verified through applying it on a number of first preparatory Student out of the Study sample. The researcher used Kurd Richardson equation 20 (KR 20) to calculate the reliability coefficient which reached approximately 0.80. To analyze the performance of the Student in the Pre Test, (T) test was used to make sure of the equivalence between the Two groups in their previous acquisition of those Concepts. The results of this analysis showed that the Two groups were equivalent. The researcher relied on the semi-empirical approach in his current Study. However, to analyze the performance of the Student in the Post Test, he used (2 way ANOVA) to examine the effect of the used teaching Method, the previous a Chievement level and the reaction between them in the Student acquisition of the selected Concepts. Then, the ( 2 Way ANOVA )was formed as 2 X 3 in which the teaching Method had Two Levels and the previous a Chievement level had Three levels. The current study has attained the following results: 1. There are no Significant differences, attributed to the used teaching Method (Gagne' Model and Klausmeiers Model), among the averages of the Student' grades in the Two groups in the aChievement test that dealt with the acquisition of the Geographic Concepts. 2. There are Significant differences, attributed to the Student previous aChievement Level (high, medium, low), among the averages of the first Preparatory Student' grades in the a Chievement test that dealt with the acquisition of the Geographic Concepts. 3. There are Significant differences, attributed to the Interaction between the used teaching Method (Gagne' Model and Klausmeier Model) and the Student previous aChievement Level (high, medium, low), in Student acquisition of some Geographical Concepts. In the light of the previous results that the Study revealed, the researcher has offered some recommendations such as the Social Studies teachers have to use the Methods of teaching Concepts that focus on providing examples and non-examples opposite pairs. The researcher also recommended that the officials in charge of the Colleges of Education in Sultanate of Oman should introduce more courses about the Methods and models of teaching Concepts in Teacher Training Programmes. Moreover, he recommended the Curriculum Development Directory in the Ministry of Education in Sultanate of Oman to attractively demonstrate the distinctive characteristics of Concepts and their examples through illustration and writing the definitions of the Concepts in the school textbook so the Student can identify them easily. The researcher, however, advised other researchers to carry out similar Studies for other Concepts, sample and instructional grades in order to reach the Study generalization. The researcher also recommended to execute more Studies that deal with Other variables such as Sex, maintaining the Learned Course and the nature of the Concept not only in Geography but also in the other domains of Social Sciences.