The purpose of this study is to examine Chinese science teachers beliefs and practice about assessment as well as the factors that affect their assessment beliefs and practice. I employed a qualitative research approach with three Chinese science teachers who taught chemistry, physics and biology, respectively. The data gathering procedures included classroom observations, interviews and document collection. The findings indicate that the teachers use assessment mainly for evaluating student performance, guiding instruction, and giving grade/score; teacher beliefs and practice about assessment are shaped by the goals for school science; the National College Entrance Examination greatly affects teacher beliefs and practice about assessment; school culture, such as administration involvement, colleagues attitudes, class size, and the length of class period affect teacher beliefs and practice. The significance, implications and limitations of the study are discussed.