Abstract:In order to supplement P. crocea Dai-qu Stock cytogenetic data, the karyotype of net-cultured P. crocea in Xiangshan Bay was studied by microscopy. PHA (8-10μg/g) and colchicine (1-2μg/g) were injected in vivo and kidney cells were subsequently collected. Then, the cells were subjected to low permeating and Carnoy’s fixation. Finally, air-drying method was performed to make chromosome samples. The results showed that the diploid chromosome number of P. crocea Dai-qu Stock was 2n=48 and its karyotype formula was 2n=24st 24t with NF=48. The relative length of chromosomes ranged from 2.60±0.43 to 5.53±0.70 in P.crocea Dai-qu Stock. Neither sex chromosome nor satellite chromosome was found. In conclusion, The karyotype of P. Crocea in this study differs from previous report.