Abstract: In this study, the full-length cDNA sequence was cloned and spatial-temporal expression pattern of Usp9 was detected by quantitative real-time PCR (qRT-PCR) for the first time from the testis of oriental river prawn Macrobrachium nipponense. The full-length cDNA sequence of Usp9 is 1259 bp, containing an open reading frame of 978 bp, 162 bp of 5’ -untranslated region (UTR), 116 bp of 3'-UTR with a poly (A) tail. The deduced amino acid sequence of Usp9 shares 99% , 97% and 95% similarity to Crassostrea gigas, Bombus impatiens and Monodelphis domestica, respectively. The phylogenetic tree based on other species Usp9 proteins showed that Usp9 from testis of M. nipponense shared the closest relationship with Daphnia pulex. qRT-PCR analysis demonstrated that the expression levels of Usp9 in M. nipponense reached the peak in the 5th day of the post- larvae (PL5), when water temperature was 28℃ . Based on the expression pattern in adult tissues, the highest expression level was observed in brain, followed by abdominal ganglion, testis, ovary, muscle and intestine. The sexually dimorphic expression of Usp9 to be significantly higher in the male mouse than female, the M:F ratios between testis and ovary, male brain and female brain were 2.86 and 2.67, the difference were extremely significant (P＜0.01). The result showed that the expression of Usp9 shared the same trend with male-biased gene (M:F≥1.5). This research could provide basic information for the function of Usp9 gene and references for further studies in genetic regulation mechanism of M. nipponense, as well as in other crustacean species.