This experiment researched the effects of Astragalus Polysaccharide (APS) on the growth and non specific immune parameters of Procambarus clarkii, with different additive concentrations (0%, 0.2%, 0.4% and 0.8%). Results showed that, 0, 2, 4, 6, 8, 12, 16, 20 d, weight gain ratio (R_WG) and specific growth ratio (R_SG) of the crayfish fitted the modified Gauss model well (R²2=0.999 9). At the concentration of 0.40%-0.75%, R_WG and R_SG reached the maximum values of 37.13% ± 7.75% and 1.57% ± 0.28% respectively. Curve of crayfish molt count (NM) was consistent with the log normal model (R²=0.997 6), with significantly different between experimental and control groups (P＜0.05), and weight gain was also significantly different (P＜0.01). Non specific immune parameters of superoxide dismutase (SOD) and acid phosphatase (ACP) changed with APS isn’t significantly (P<0.001).vely promote the growth and non specific immunity of crayfish. In addition, the suitable additive concentration was 0.40%-0.80%.