Abstract: To solve the problem of serious pollution caused by pesticide residues in soil, the research and development and application of microbial agents have become the current research hotspots, and the microbial remediation of soil has the advantages of no pollution and good effect. [Method]The highly efficient degradation strain HBT4 of this experiment was selected from the soil seriously contaminated by atrazine in the early stage, and was purified and propagated. The appropriate protective agent was selected to prepare a solid powdered fungicide by spray drying and the process conditions were performed.By using the orthogonal test method to optimize the process conditions.[Result] The optimum conditions for the exploration were as follows: Peristaltic pump speed 15%, hot air flow rate 35L.h-1, ratio of protective agent to sludge (V:V) was 3:1 and inlet temperature was 170℃. The water content of the product obtained under the optimum process conditions was 4.42%, the number of viable cells was 1.45×109 cfu/mL, and the viability of the cells was 82.6%. [Conclusion] The degradation agent of HBT4 obtained by the spray drying method under the optimum process conditions has a good degradation effect on atrazine, which will provide a good bacterial species resource for the development of the microbial degradation microbial agent of the herbicide in the future.