This research was aimed to develope computer assisted learning by using Microsoft Excel based on Van Hiele theory in Trigonometry of Senior High School grade X. The development of this learning media followed the procedure proposed by Plomp which has five phases: (1) preliminary investigation; (2) design; (3) realization/construction; (4) test, evaluation and revision; (5) implementation. As a matter of fact, this research was conducted until phase test, evaluation and revision so that the result was until in the form of final prototype and ready to be implemented in wider area. The results showed as follows. (1) Learning Media is the media attention to the level of student thinking and help students in solving mathematical problems. (2) Media learning developed through the following phases, preliminary investigation; design; realization/construction; test, evaluation, and revision. (3) Learning media is valid, practical, and effective. (4) Development of learning media to improve achievement and student motivation to learn mathematics. Based on the result of this research, it was suggested that the teaching and learning math in Senior High School grade X, especially Trigonometry material to use assisted learning media by using Microsoft Excel based on Van Hiele theory. Moreover, the developing media in this research could be used as an example for practitioner and teacher in developing their learning media which is in line with the characteristics and the process for obtaining good quality of the media.