For studying the effects of surfactant in the nitration of m-xylene,the influence of the types and the amount of the surfactant,strength of nitro-sulfuric acid and reaction temperature were investigated. The results show that surfactant improves the selectivity and the conversion of the nitration of m-xylene. Under the optimized reaction conditions,the ratio of 2,4-dimethylnitrobenzene to 2,6-dimethylnitrobenzene is 11.8，and the conversion of the nitration of m-xylene can reach 100%.