OBJECTIVE：To choose the best process to clear impurity.To fix the type and filling capacity of capsule.To provide the relative humidity of workshop.METHODS:The nature of extract prepared with different methods were studied.The pile-density and critical relative humidity were determined.RESULTS:The extract that was prepared by high-speed centrifuge was easier to dry.The fluidity of the powder was better.The hygroscopicity of the powder was lower.CONCLUSION:The high-speed centrifugal method was chosen.The type of capsule was defined as 0#.The package was 0.45 gram for each capsule.The relative humidity of workshop was below 54%.