Based on the analysis of the characteristic of various constraints in equipment maintenance task routing plan, a model of equipment maintenance task routing plan is established. In the model, the influence of time constraint and load capacity constraint is fully considered. Through comparing similarities and differences between the equipment maintenance task routing plan problem and the traditional vehicle routing problem, a maintenance task routing plan method based on improved maxmin ant system (MMAS) is presented. Rules of selecting maintenance, pheromone updating and acquiring prior information of MMAS are improved. Finally, through an example and comparison, the verifiability and effectuality of the algorithm are verified.