In order to solve problems such as skin irritation to human body and high toxicity to aquatic organisms during the process of using, the lambda-cyhalothrin microcapsules were prepared by solvent evaporation method using ethyl cellulose as wall material and dichloromethane as solvent, and the physical and chemical properties and slow-release characteristics of the microcapsules were characterized. L9 (34) orthogonal experiment was designed, comprehensive score composed of average particle size and unencapsulation rate was adopted, to establish the optimum preparation conditions. They were as follows: 25% methylene chloride, 0.75% ethyl cellulose, 2% emulsifier, and shear for 8 min. The microcapsules had uniform particle size and smooth surface through observation by scanning electron microscopy; The infrared spectrogram showed that the lambda-cyhalothrin were encapsulated by ethyl cellulose; Release characteristic curve showed that microcapsule had good slow release performance. The process has the advantages of simple operation, short preparation period and excellent encapsulation, it can provide one effective way for the preparation of pesticide microcapsules.