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聚乳酸(PLA)由于良好的生物相容性和可降解性已被广泛应用于医学领域. 以聚乳酸为载体材料制备农药传输系统可有效防止敏感型药物降解,延长农药的持效期. 采用乳化-溶剂挥发法(O/W)制备了聚乳酸纳米微球,考察了表面活性剂的种类及浓度、有机相和水相体积比、聚乳酸浓度等因素对纳米微球粒径大小的影响,用扫描电子显微镜和透射电子显微镜对纳米微球的形貌进行表征,用纳米激光粒度仪对纳米微球的粒径和多分散指数进行了表征. 结果表明:选择Tween20为表面活性剂,当Tween20浓度为0.01～0.03g/mL、聚乳酸浓度为0.02g/mL、有机相与水相比为1:10,通过超声乳化可制得粒径为230～250nm的纳米微球,并具有较好的分散性和成球性. 进一步制备了聚乳酸-嘧菌酯纳米微球,表面活性剂的浓度是影响粒径的关键因素,当Tween20浓度为0.03g/mL,所得纳米微球的粒径为236nm,包封率和载药量分别可达81.38％和27.11％. 本研究可为环境友好型聚乳酸纳米农药缓释微球的制备提供技术和参数支持.“,”Polylactic acid (PLA) has been widely used in the medical field, because of its good bio-compatibility and bio-degradablity. The preparation of pesticide delivery system with PLA as carrier can effectively prevent the degradation of sensitive drugs and prolong the duration of pesticide. This experiment prepared poly lactic acid nano-microspheres by emulsion solvent evaporation method (O/W); investigated the effects of surfactant kind and concentration, volume ratio of organic phase to aqueous phase, concentration of PLA, etc. factors on the size of nano-microsphere; characterized its morphology by scanning electron microscopy and transmission electron microscopy;and also characterized the particle size and polydispersity index by particle size analyzer. The results indicated that choosing Tween20 as surfactant, when Tween20 concentration was 0.01～ 0.03 g/mL, PLA concentration was 0.02 g/mL and ratio of V(oil phase):V(aqueous phase) = 1:10, the nano-microsphere with 230～250 nm particle size could be prepared by ultrasonic emulsification. These nano-microspheres had better dispersibility and spheronization. The PLA-azoxystrobin nano-microspheres were further prepared. The results showed that the surfactant concentration was a key factor affecting the particle size. When the concentration of Tween20 was 0.03 g/mL, nano-microspheres with 236 nm particle size could be obtained. The entrapment efficiency and drug-loading rate were 81.38％ and 27.11％, respectively. This study provided technical and parameter support for the preparation of environmental-friendly PLA sustainable release nano-microspheres for pesticide.