The role of grammar in language teaching has always been the question that researchers debate.In recent years,grammar knowledge has been distinguished in the foreign language acquisition research,namely the implicit knowledge and the explicit knowledge(Dai Manchun 2005;Gu Qiyi 2005).As to the reaserch of implicit and explicit grammar knowledge as well as their measurement,it is easy to find that many scholars have studied the role of two different kinds of grammar knowledge in second language development.But the research on the role of implicit and explicit grammar knowledge in second language reading comprehension is too few,not to mention the research on the role of implicit and explicit grammar knowledge in English reading comprehension in the senior high school.The purpose of this study is to find the relationship between implicit and explicit grammatical knowledge and English reading comprehension ability of senior high school students.In addition,since the vocabulary is important to reading comprehension,this factor will also be considered in the study.