The present study has been carried out for the purpose of evaluating the effects of different levels of soybean and Avizyme multi enzyme supplement on hematological and biochemical parameters in serum of rainbow trout following 60 days of trial. The basis of tested diet formulation in this paper was the substitution of 0%, 25%, 50%, 75% and 100% of the fish's soybean protein with the soybean protein and use of different amounts of Avizyme multi enzyme with 0, 500, and 1000 ppm dosages in the diets under 13 experimental treatments. At the end of trial period, blood samples have prepared through caudal peduncle vein from 195 normal fish, looking healthy (with the weight average of 127.91±15.57g). Based on the results, the highest amount of WBC was observed in diet with 50% soybean protein accompanied by 1000 ppm Avizyme multi enzyme supplement which had a significant difference compared to the other treatments (P<0.05). Moreover, the PCV, total protein and globulin had the highest amount in this treatment with no significant difference (P>0.05). Adding the amount of soybean in the diet, concentrations of glucose, cholesterol, triglyceride, ALT and ALP, the displayed a significant redused compared to the control treatment (P<0.05). Overally, it can be rectified that the diet with 50% soybean protein accompanied by 1000 ppm Avizyme multi enzyme can have positive effects on hematological and biochemical parameters of serum in rainbow trout.