The importance of this study emerges from the importance of the points it discusses as it attempts to study the effectiveness of the suggested program of mathematics that develop the thinking skill of the children in preschool age. Accordingly, it comes from the attempt to teach the children the skill of thinking as one of the important and required skills for the children to accommodate with the surrounded environment and to help them develop and grow completely and to accommodate with themselves and their society. The purpose of this study is, thus, summarized in the answering of the following questions: 1- How can we create a program that uses mathematical activities and that contribute in the development of thinking skill of the preschool child? 2- To what extent is that program effective to develop the skills of thinking of the preschool child? The research sample is composed of 35 children for the experimental group and the same number for the controller group from the KJ2 children. The results of the research showed the effectiveness of the suggested program and its obvious contribution in the development of the thinking skills for the preschool children in a more effective way than the traditional methods used.