The variations on muscle composition and innate immunity of the Japanese sea perch, Lateolabrax japonicus, which experienced starvation and refeeding were studied in this paper. Four treatments were designed. S0 group was treated as control for normal feeding during the experiment phase. S5, S10 and S15 groups were fasted for 5 d, 10 d and 15 d respectively and then refed as normal as the control. Fish were sampled every 5 days from the control group, or at the end of starvation and every 5 days during the refeeding phase from the experiment groups for assays on muscle composition and innate immunity. The results indicate that there are significant effects of starvation on muscle compostion. Compared to that of the control, the fish from S10 group have a significant lower lipid content and the fish from S15 have significant lower lipid and protein contents while higher moisture in muscle at the end of starvation. It is suggested that lipid prior to protein in muscle is used as an energy source during starvation for Japanese sea perch. During the refeeding phase, the muscular lipid content of the fish from S10 group and S15 group continue to decrease to some extent then increase to the control level. While the muscular protein content of the fish from S15 increased as refeeding begun. It is suggested that the Japanese sea perch which experienced starvation restore protein prior to lipid in muscle during refeeding. The fish from S15 group have a significant lower protein concentration in serum at the end of starvation. Compared to that of control, there is no significant variations on lysozyme activities in serum, spleen and head kidney of the fish from S5 group. After 10 d refeeding, the fish from S10 group have a compensatory increment of lysozyme activity in head kidney. The phagocytosis activities decreases after the fish experienced starvation. The fish from S5 group have a compensatory increment of phagocytosis activities after 15 d refeeding while the fish from S10 group and S15 group do not display the comensatory increment of phagocytosis activitis. It is therefore suggested that starvation and refeeding also affect the innate immunity of Japanese sea perch and a resonable starvation regimen will improve the innate immunity of the fish.