The invention relates to a preparation method of permethrin microcapsules. The preparation method comprises the following steps: (1) carrier preparation: carrying out a polymerization reaction on succinic acid, butanediol and lactic acid according to a ratio being 1: 1: (0.2 to 0.3) to obtain a carrier PBS-co-PLA (polybutadiene-styrene-co-Poly Lactic Acid); (2) oil phase preparation: weighing various components, namely PBS-co-PLA, permethrin and dichloromethane according to a mass ratio of (3.5 to 4.5): 1: 10, dissolving the PBS-co-PLA carrier in the dichloromethane, then adding permethrin technical after complete dissolution, and dissolving to obtain an oil phase; (3) water phase preparation: weighing deionized water according to a mass ratio of the oil phase to the water phase being 1: (5 to 7), adding an emulgator and a dispersant, and dissolving to obtain the water phase; (4) microcapsule preparation: adding the oil phase to the water phase to obtain an oil-water mixed emulsion, adding a defoaming agent, curing to form a microcapsule suspension, washing with water to remove supernatant, and drying to obtain the finished product. The method disclosed by the invention is simple in process and environment-friendly. The obtained permethrin microcapsules are better in shape, have the encapsulation efficiency reaching 78 percent, the drug loading capacity reaching 50 percent, the effective release period reaching 30 days and the drug release amount reaching 94 percent, and are of an ideal pesticide slow release agent.