According to gene sequences, penaeidins (one kind of antibacterial peptide in shrimps) in genome of Chinese shrimp, is, could be assorted into three kinds. In order to explore the expression differences among the three penaeidins after WSSV challenge, real-time quantitative PCR was used to detect the expression characteristics of these penaeidins at different time after WSSV challenge in Chinese shrimp. hrimps used in the experiment came from the same parentage. After fed each individual the same dose of WSSV, 3−6 samples were collected at 0 h (uninfected), 6 h, 12 h, 24 h, 48 h, 72 h, 96 h, 120 h and 156 h after infection. The individuals dying in three days were regarded as WSSV-susceptive population, while those still living after seven days were regarded as anti-WSSV population. The results showed that the expression of penaeidins was tissue specific in four tissues of hepatopancreases, muscles, gills, and intestines, and the richness of expression and expression tendency from 0 h to 156 h was significantly different (<0.05). However, as far as one tissue was concerned, the tendency of expression for three penaeidins was similar in the period from 0 to 120 hours after challenge. For example, the expression of three penaeidins’ mRNA in hepatopancreas was 0 at 0 h, and increased at 6>0.05). It seemed that the penaeidins of shrimps might mainly take part in resisting bacteria, not in resisting WSSV.