The karyotypes of Triomyx sinensis in Nanjing, Jiangsu and Shaoxing, Zhe jiang have been studied in this paper. The results showed that the karyotypes of them were identical. It was 2n = 66 = 4M 8SM 16T 38m, NF=78, 6 8 19 (karyotype formulas).It have been found that the absolute length and the relative length of them were different.The fifth SM chromosome is the smallest of the macrochromosomes in the turtle of Nanjing.While it was equal long with the first T chromosome in the turtle of Shaoxing. In addition,the arm ratios of them were different, but the difference was not significant (P>0.05). The karyotypes of Trionyx sinensis and Testudinidae have also been compared in the paper. It was discussed from the field of systemtical evolution.