At present, many invertebrates have been proved that they do have immune priming, but the relevant mechanisms are still unknown. In this study, the crabs stimulated firstly by heat-killed V. parahaemolyticus or injected by physiological saline were challenged again at 168 h by live V. parahaemolyticus (HkVp+Vp group and spss+Vp group respectively). The survival rate of HkVp+Vp group at 72 hours was 20.66% higher than that of spss+Vp group. In the serum, the AKP activity of the HkVp+Vp group was significantly higher than that in the primary immunization group (HkVp group) and spss+Vp group at the early stage of infection, the LYS activity was significantly higher during the entire infection period than HkVp group and spss+Vp group (except 3 h), and the ACP activity was lower in the entire infection period than spss+Vp group, but there was no significant difference (except 6 h and 12 h). In the hepatopancreas, the activities of AKP, ACP, and CAT were significantly higher in the early stage of infection than HkVp group and spss+Vp group. The activities of LYS and T-SOD were higher in the whole infection than spss+Vp group, but there is no significant difference. By comparing the gene quantification results in the hemocytes and hepatopancreas of HkVp+Vp group and spss+Vp group, the molecules that may play a role in the early stage of the immune priming process of the crab in the hemocytes are Dscam, PPAF1, Serine, Hyas, AKP, CAT, SOD, TPx, TNF, MIF, Cactus, ALF3, ALF4, ALF5, and ALF6, and later acting molecules are Cru, LITAF, Pero, Hemo, MyD88, and Tube. The molecules that function throughout the entire period are: C-lectin, FREP, iNOS2, Spaetzle; In the hepatopancreas, the molecules that may play a role in the early stages of the immune priming include: Dscam, PPAF1, Serine, Hyas, AKP, CAT, SOD, ALF6, TNF, MIF, Pelle, Spaetzle, Dorsal, and later stage include LITAF and Pero. The molecules that function throughout the entire period are C-lectin, Tube, Tpx, Cru, and ALF5. In summary, the immune function of the crabs was enhanced when they received the same Vibrio repetitive stimulation, indicating the presence of immune priming in the mud crabs.