Abstract: The purpose of this study was to investigate the effects of cottonseed protein concentrate (CPC) instead of soybean meal on the growth performance, health status and flesh quality of grass carp (Ctenopharyngodon idella). Six isonitrogenous (crude protein: 29%) and isolipidic (crude lipid: 5%) diets were designed. CPC was used to replace 0 (C0), 15% (C15), 30% (C30), 45% (C45), 75% (C75) and 100% (C100) soybean meal in grass carp diets. The grass carp initial weight of (502.46±0.40) g were fed in pond cages for 90 days. The results showed that: (1) In terms of growth performance, there was no significant difference in specific growth rate (SGR) and feed conversion ratio (FCR) among groups (P>0.05). The viscerosomatic index (VSI) of grass carp in C45 group was significantly higher than that in C0 group (P<0.05). (2) In terms of health status, the albumin and globulin ratio (A/G) of serum in C100 group was significantly lower than that in C0 group (P<0.05), and the activity of serum superoxide dismutase (SOD) in C15 group was significantly higher than that in C0 group (P<0.05); There were no pathological changes in liver and muscle tissue of grass carp in each group. (3) In terms of flesh quality, compared with C0 group, the crude protein content of grass carp muscle in C75 group and the isoleucine content of C30 group increased significantly (P<0.05), the muscle springiness and adhesiveness of grass carp in C30, C45 and C100 groups increased significantly (P<0.05), and the sarcomere length of grass carp muscle in C75 and C100 groups increased significantly (P<0.05). The results showed that CPC can completely replace soybean meal in grass carp diets, improve its immunity and flesh quality.