In this study, the full-length cDNA of UB-E2 was obtained using RACE technology in Procambarus clarkii. The expression of UB-E2 gene in different tissues and development stages and the expression of UB-E2 and gonadal development after hormone stimulation by 17α-hydroxyprogesterone were studied by RT-PCR. The results showed that the gene has a full-length sequence of 3 943 bp, an open reading frame of 675 bp, encoding 224 amino acids, a relative molecular weight of 23.93 ku, and an isoelectric point of 8.61. Its amino acid sequence from 82 to 219 is unique protein domain of the ubiquitin-conjugating enzyme family. The amino acid sequence alignment showed that UB-E2 gene of Procambarus clarkii had higher homology with arthropod UB-E2 gene. Phylogenetic analysis showed that the UB-E2 gene was clustered with L. vannamei and P. monodon. Quantitative fluorescence results showed that the expression of UB-E2 gene in ovary tissue of Procambarus clarkii was significantly higher than the other tissues (P < 0.05); it was the lowest in the early stage of ovarian development, then it gradually increased, and it began to decline in the late spawning period; 17α-hydroxyprogesterone stimulation results showed that the ovarian development of the experimental group was significantly accelerated, while the UB-E2 gene expression was also significantly increased, ovarian development and UB-E2 gene expression were consistent with 17 α-hydroxyprogesterone stimulated response. It is speculated that UB-E2 gene plays an important role in ovarian development and gametogenesis in Procambarus clarkii. This study will provide a theoretical basis for the molecular regulation of gonad development in Procambarus clarkii.