Preparating the ivermectin(IVM) poly-lactic acid(PLA) microspheres by emulsified solvent evaporation method, and the research prepared the injection of the microspheres and established its quality control standards. Applying Central Composite to optimizing three factors which affect microspheres preparation including stirring speed, mass ratio of IVM:PLA and polyvinyl alcohol(PVA) concentration. The research used the orthogonal experiment to optimizing the suspension system, prepared the IVM microspheres injection and evaluated its quality control standards. The results suggests that the optimal microspheres preparation condition is 651r/min of stirring speed, 7:16 of the mass ratio and 1.47% of PVA, and under this condition the drug loading rate is 29.4%. The optimal suspension system is that the particle diameter is 80μm, and the contents of the microspheres, Tween 20 and sodium carboxymethyl cellulose are 2.5%, 1.5% and 1% respectively. The sedimentation volume ratio of the injection is 91.5%. Being evaluated the injection average pH is 7.2, and the effective component stably releases in 20 days in vitro which achieves sustained releasing effect. The preparation process lays the foundation the development of ivermectin sustained-release microsphere for injection and its safety application of the clinical usage.