Non-cognitive variables are important indicators for students’ achievement. The study examines the relationship between non-cognitive variables and science achievement using PISA 2015 data at both student- and school-level for the United State and China. The findings show most non-cognitive variables have significant impacts on science outcomes and have same patterns in both countries at student- level. The effects of some of these variables also vary significantly across schools. Additionally, we also see that there are differences between two countries in terms of how non-cognitive variables affect students’ science achievements. And schools appear to be more important for Chinese students.