This study aims to explore non-English speaking major students' perceptions of Motivation and Grit and the relationship between these two factors and students' English language performance at a public university in China. The research was conducted by quantitative research design to collect 624 non-English speaking Major students' answers to multiple questionnaires at a public university in China. Data analysis is used by SPSS and AMOS. The study shows that Motivation and Grit all have a positive correlation with English language performance. One major conclusion of this study is Grit has the most significant effect on the English language performance of non-English speaking major students in multiple regression analysis and is also the best predictor of the relationship between these two factors and English language performance in the path analysis in Structure Equation Modeling (SEM) analysis. The finding also revealed that male students' perception of motivation and grit is slightly stronger than that of female students. These findings highlight the need for English as a foreign language (EFL) teacher to understand students' affective factors in learning English, and hence help them utilize different teaching methods to enhance students' English learning and promote sustainable development of English learning in a public Chinese university.