This study aimed to conduct a comprehensive investigation into the Mathematics Writing (MW) of Chinese students. We conducted a comparison between MW and general writing on organizational features. The analysis was based on a sample of 138 sixth-grade students. Our findings revealed: (a) students demonstrated significantly higher performance in all organizational features of general writing than MW; (b) students utilized a few mathematics vocabulary and displayed one to two grammatical errors in MW, indicating challenges in these areas; (c) students often used procedural knowledge in their MW. Collectively, these findings suggested similar to U.S. students, Chinese students encountered challenges when transferring general writing skills to MW. Explicit instruction and feedback on MW may be necessary.