Because the ordinary pumps can't be realized “zero leakage” in conveying inflammable, explosive, poisonous and harmful medium in large-scale chemical enterprises, magnetic pump was used in the unit in an annual output of 5×105 tons of methanol and 2×105 tons of dimethyl ether of large-scale coal chemical industry, and has never been a material leakage accident during eight years of running. The structure characteristics of magnetic pump were introduced in this paper. Combined with the pump running situation rate in the coal chemical enterprises, the reations of causing the flow of magnetic pump to be reduced, the bearing parts of the pump to be damaged, rotor to be demagnetized were described. Meanwhile maintenance measures of magnetic pump were introduced.