The mechanism of 2-cyanopyrazine prepared from 2-methylpyrazine (2-MP) by catalytic ammoxidation has been explained by the theory of appropriate structure of group. A new catalyst of MoVPO was developed. The effects of catalyst promoter phosphorus and supports were investigated. The catalyst containing P, V and Mo in molar ratio of 1.4: 1 :0.02 and supported on activated alumina and prepared by impregnation method exhibits good activity and selectivity. Reaction factors such as reaction temperature, space velocity, feed composition and service life of catalyst were investigated. Optimum reaction conditions (the volume space velocity of 0.2h(-1), the reaction temperature of 380 degrees C and molar ratio of 1 :7.8: 8 :8 for 2-MP, water, oxygen and ammonia) were obtained. Selectivity of 93% and yield of 86% could be achieved under these conditions.