Abstract: Bacillus amyloliquefaciens bio-control strains B1619 showed good control effects to soilborne diseases for greenhouse vegetables. In order to minimize the impact of the formulation technology to the containing bacteria number of water dispersible granules bio-fungicide B1619, the ratio of main additives in the water dispersible granule of B1619 and the preparation conditions were optimized based on single-factor filter and orthogonal experiment. Test results showed that:the best ratio combination of 3 main additives is:silicate magnesium aluminum 1%, naphthalene sulfonate formaldehyde 3%, ammonium sulfate 4.5%. After the optimization, the containing bacteria number of water dispersible granules has improved by 152.0% compared to the initial value. And the best particle preparation condition combination of 3 main factors is:grain diameter 1.5 mm, drying temperature 65℃, and drying time 20 min. After the optimization, the amount bacteria of water dispersible granules has increased by 160.0% compared to the initial value. Validation test showed that, after optimization, the amount bacteria of B1619 water dispersible granules was improved to 1.05×109 cfu/g, given the value before optimization was 2.50×108 cfu/g, the rate of optimization was 320.0%. In conclusion, the optimization effect of this study on formulation was remarkable.