This paper uses the method of educational production function and hierarchical linear model to analyze the determinant factors of education quality in rural secondary schools in the Gansu province with the data of "The Gansu Survey of Children and Families in 2004".Results show that education quality in rural secondary schools in the Gansu province varies significantly among the student-level,the class-level and the school-level.The socio-economic status of student family and school peers put significantly effects on education quality.Teacher quality makes an important effect on education quality.The class size has a significantly negative effect on education quality.The decentralization of administrative power in school has a significantly positive effect on education quality.Based on the above findings,four aspects of policy suggestions are put forward to improve the education quality for the rural secondary school in the west of China: reducing the class size,improving teacher quality,setting up a system for protecting rights and interests of unauthorized teachers,promoting the decentralization of administrative power in school.