An increasing number of research is focusing on L2 grit, which plays a significant role in SLA. But few studies examine the factors that affect L2 grit. This study investigates the internal predictors influencing L2 grit in Chinese college students, specifically focusing on L2 willingness to communicate (WTC), L2 anxiety and L2 joy. A structural equation model (SEM) is constructed to examine these relationships. There are 148 valid final questionnaire survey participants. The findings reveal that both L2 WTC and L2 joy positively and directly predict L2 grit; while L2 anxiety has a direct negative effect on L2 grit; and there is a significant correlation among L2 WTC, L2 anxiety as well as L2 joy. This research contributes to the field by promoting further studies on L2 grit, and adds to pedagogical implications for teachers to take appropriate teaching methods that enhance students' level of L2 grit so as to promote foreign language learning.