This study aimed at investigating the effect of using CaRMetal software in the acquisition of the geometrical concepts and spatial reasoning of eighth grade students by answering the research questions: 1 .What is the effect of using the CaRMetal software in the acquisition the geometrical concepts of eighth-grade students? 2 .What is the effect of using the CaRMetal software in the spatial reasoning of the eighth-grade students? To achieve the objectives of the study, an intentional sample of (65) female eighth grade students was selected from a school in the Governorate of Muscat in the second semester of the academic year (2017/2018). Random assignment was used to distribute the students into two groups: an experimental group which had (33) students studied (the learning content) using CaRMetal software, and a control group which had (32) students studied (the same content ) in the traditional way. The implementation of the study required the preparation of the learning materials for the geometry unit of 8th grade using CaRMetal software. Also, a test in the acquisition of geometrical concepts consisting of (17) questions and a scale of spatial reasoning consisting of (92) items were developed. The validity and reliability of the research instruments and tools were assessed and found acceptable for the study. The results of the study showed that there was a statistically significant difference at the level of (a = 0,05) between the scores averages of the experimental group and control group in the acquisition of the geometrical concepts and the spatial reasoning scale in favor of the experimental group. In light of these results, the researcher recommends the need to activate the use of (CaRMetal) software in teaching various geometrical topics, further studies that investigate the impact of using this software on other variables are recommended.