This research is intended to know the content validity of the English summative test of the first semester for the tenth grade of SMA Muhammadiyah 3 Tangerang 2009/2010. The population of the research is the first semester English summative test for the tenth grade in the academic year 2009/2010 in SMA Muhammadiyah 3 Tangerang which was administered on Monday, December 07, 2009. The research method used to know the content validity the English test for senior high school is descriptive comparative analysis method by analyzing and comparing the content of the English summative test to the content of KTSP (School Based Curriculum) for senior high school. From the analysis the writer finds out that the English summative test which was administered by SMA Muhammadiyah 3 Tangerang has appropriate content validity. The percentage of objective and material of reading skill is 94% and 100%, whereas the percentage of writing objective is 2% and the material is 2%.