The research aims to investigate the effect of using the strategy of Conceptual Maps in the unit of Differentiation and the development of inductive thinking among the high schools\' students (Scientific section). The sample of the research consisted of (122) students divided into four divisions, two divisions of (59) students as a group officer, and two divisions of (63) as experimental group. In order to educate the experimental group, the researcher developed a set of conceptual maps related to the Differentiation, and used the reasoning test that was prepared by Al Khazraji (2007), and an achievement test in calculus prepared by the researcher. The results revealed statistically significant differences in average levels on the sample students of achievement test for the experimental group, and the existence of statistically significant differences in average levels of the experimental group to test the reasoning. In addition, the results also showed statistical differences betweens the grades of the students sample attributable to the method and gender and the interaction between them. In the light of these results, some of the recommendations have been provided.