is one of the most economically important cultured shrimp species in the world. However, the frequent occurrence of various shrimp diseases has brought severe economic losses to the aquaculture industry. Moreover, the growth and development of are also affected by unstable aquaculture water. All of these restrict the healthy development of only relies on innate immunity to protect itself from external invasion. Therefore, it is very important to analyze its immune response and salinity adaptation mechanisms. Mitogen-activated protein kinase kinase 7 (MKK7) is a key regulator of the c-Jun N-terminal Kinase signaling pathway. It is involved in regulating cell response to a variety of extracellular stimuli. In this experiment, the full-length cDNA sequence of MKK7 ( was cloned by rapid amplification of cDNA ends (RACE) technology and the sequence was biologically analyzed. The full-length cDNA consisted of 2710 bp with a 1410 bp open reading frame, encoding 466 amino acids. In its conserved kinase domain, a serine/threonine protein kinase (S-TKc) region is a potential site for activation by upstream genes. The results of multiple sequence alignment and phylogenetic tree analysis showed that genes were clustered together and had the highest homology:99.14%. The quantitative real-time PCR (qRT-PCR) analysis shows that was ubiquitously expressed in all tested tissues. The highest expression level was in muscle tissue and the lowest expression was in stomach tissue. Following a bacterial injection experiment, the groups infected with had significantly higher expression in the hepatopancreas and gills than the control group (, expression in both tissues was significantly lower than the control group. After low salinity (17, 3) stress, the expression levels of in hepatopancreas and gill tissues was significantly up-regulated. After the increased significantly under low salinity stress, and the expression of in the downstream gene of the MAPK signaling pathway was inhibited. The results show that the JNK signal transduction pathway may play an important role in the immune defense and salinity stress tolerance of . It is hoped that more studies on the JNK signaling pathway will be conducted in order to better understand the innate molecular immune mechanisms of .