This study aims to explore the relationship between Chinese college students’ motivational regulation strategies and their academic writing performance under the English as a foreign language (EFL) context. Quantitative and qualitative methods were both applied in this study. Around 250 sophomores studying at Shanghai University of International Business and economics (SUIBE) were asked to finish an online questionnaire and a writing task. Among the participants, 30 students from high writing-proficiency (n=15) and low writing-proficiency (n=15) groups were invited to semi-structured interviews to answer follow-up questions. Quantitative data showed that students with higher writing scores intend to use more interest enhancement, mastery self-talk and environment structuring strategies than students with lower writing scores. The interviews also revealed that high writing-proficiency group are more familiar with these strategies and are more flexible while using them, yet the low writing-proficiency group has limited understanding of these strategies. In addition, the factors affecting these two writing-proficiency groups are also explored. The study has found that background knowledge regarding writing topics, social support and knowledge about learning strategies can exert positive influence on their writing performance.