This study aimed to clarify the effect of the teaching that based on proportionality problem solving strategies in acquiring the concepts of ratio and proportional and proportionate thinking of six grade students. The study used semi experimental method and it was applied to a sample of the sixth grade students who were divided into two groups. An experimental group of (30) students which was taught by using proportionality problem solving strategies and control group which consisted of (31) students and was taught by using the tradition method during the second semester of academic year (2017-2018). The researcher applied two tests for the members of study, the first one is acquiring the concepts of ratio and proportionality test which consisted of (15) multiple choice questions. The second test was proportional thinking test which consisted of (6) multiple choice questions. The data were analyzed by using ANCOVA to examine the significance of the difference between the average scores of the control and experimental group students. This study showed there is a statistically significant differences at the level of (a=0.05) between the students' scores average of the experimental group students and the control group students in acquiring the concepts of ratio and proportionality and proportional thinking in favor of the experimental group due to the teaching strategy. Based on these findings, the researcher recommends the curriculum designer for grade 6 to include proportionality problem solving strategies in the unit of ratio and proportionality and to implement workshops for teachers on how to use these strategies and methods in teaching.