Abstract: 【OBJECTIVE】The experiment was conducted to study the effect of different levels of copper and manganese on plasma antioxidation parameters of Holstein bulls. 【METHOD】Forty Holstein bulls were randomly divided into ten treatments. The control group was fed with basic diet the others were fed with three levels of copper 4, 8, 12mg/kg (on the basis of dry matter ) and three levels of manganese 50,125,200mg/kg (on the basis of dry matter ) in the basal diet Experimental design was used by 3 × 3 trial design. The experiment lasted 8 months. 【RESULTS】The results indicated that the activities of GSH-Px, SOD, Mn-SOD and the content of NO was the extremely significant（P<0.01）when basic diet was added different levels of copper and manganese , the significant difference of the activities of T-AOC and CuZn-SOD（P<0.05）, and not significant difference of the activities of CP, CAT and the content of MDA (P>0.05). 【CONCLUSION】It was concluded that basal diet supplementing with 4-8mg/kg copper and 50mg/kg manganese were the optimal supplementation in this experiment according to analysis of all blood antioxidation parameters.