Objective: To optimize ultrafine grinding process of Chuanxiong Rhizoma. Method: Taking feeding amount

moisture content and grinding time as independent variables

average particle size as dependent variable

Box-Behnken response surface methodology was adopted to optimizeultrafine grinding process of Chuanxiong Rhizoma

its powder properties and hygroscopicity before and after smashed were investigated. Result: Optimum ultrafine grinding process was as follows:feeding amount1.3 kg

moisture content 4%

grinding time 19 min;Deviation between the predicted value(18.357 7 μm) and the measured value(19.187 μm) of average particle size was only 4.5%.Response angles of ordinary and ultrafine powder were (49.4±0.03) and (50.2±0.02) °

bulk densities were (0.429±0.003) and (0.363±0.005) g·mL-1

tap densities were (0.609±0.05) amd (0.556±0.10) g·mL-1

moisture equilibrium times were about 80 h. Conclusion: Optimized ultrafine grinding process was reasonable and feasible

preparation technology of ultrafine powder of Chuanxiong Rhizoma should add flow aid and other auxiliary materials in order to improve fluidity of powder

ultrafine grinding process should strictly control humidity.