Grammar is "a system of rules governing the conventional arrangement and relationship of words in a sentence" (Brown 1994) which can facilitate the acquisition of a foreign language and is conducive for cultivating comprehensive language competence. Most teachers regard grammar as a frame of English learning. The grammar teaching beliefs held by teachers can affect their practical teaching behaviors in class, thus can have different teaching results in the end. Therefore, through quantitative and qualitative research, this paper aims to investigate the present status of grammar beliefs of high school students as well as teachers' beliefs and their grammar teaching behaviors, analyze and compare the similarities and differences between them. The result shows that teachers' grammar teaching has the tendency of communicative teaching while students' grammar beliefs have the characteristic of integration of communicative and traditional grammar teaching. Teachers' grammar teaching behaviors can basically be consistent with their grammar teaching beliefs.