Abstract: 【Objective】 To compare the effects of polyinosinic acid(Poly I:C) stimulation on immune factor activity and gene expression related to interferon system in Siniperca chuatsi, and to provide a reference basis for estimating and guiding immune response and virus monitoring after pathogen stimulation in S. chuatsi culture.【Method】 Using Poly I:C to mimic viral stimulation, the percentage of leukocyte composition of S. chuatsi at different time sequences(0, 3, 6, 12, 24, 36, 48 and 72 h) after injection was compared and double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was used to detect changes of complement protein and relative expression of immune related genes by real-time fluorescence quantitative PCR.【Result】 In the percentage of blood leukocytes, thrombu > monocyte > lymphocyte > neutrophil, among which, in the treatment group, the percentage of monocytes in the treatment group increased extremely significantly from 6 to 72 h(P<0.01, the same below) and returned to the initial level after peaking at 48 h. The percentage of neutrophils increased significantly, and the percentages of lymphocytes and thrombus cells decreased. Serum complement C3 in the treatment group were higher than that in initial level after 3 h, lower than initial level at 6 h, significantly different from that in control(P<0.05, the same below). Complement C4 levels in the treatment group were significantly higher than the control group at 3 h and significantly lower than the control group at 6, 24 and 48 h. Compared with initial 0 h, the expression of IRF7 gene in kidney, liver, spleen and thymus in the treatment group was extremely significantly upregulated from 3 h and from 6 h, and the expression in thymus was the highest; the expression of IFNh gene in kidney and liver in the treatment group was extremely significantly up-regulated at 3 h, peaked in thymus appeared at 6 h, and decreased again at 12 h, IFNc gene in spleen at all times were loner than initial time; the expression of IFNc gene in kidney, thymus, liver and spleen in the treatment group was extremely significant up-regulated at 12 h and then gradually decreased and reached the minimum at 72, 72, 48 and 72 h.【Conclusion】 S. chuatsi after virus stimulation mimicked by Poly I:C, various types of leukocytes in blood cells, serum enzyme complement C3 and C4 change differently, and interferon significantly affects expression changes in various tissues at different time sequences.