Abstract: OBJECTIVE To optimize the formulation and investigate the hygroscopicity of New Five-juice Decotion granules, so as to provide a basis for developing new five-juice decoction granules into herbal cuisine plain food. METHODS Appearance, clarity, melting, color, mouthfeel, etc were used as evaluation indexes. The amount or ratio of excipients in formulation of New Five-juice Decoction granules like the diluent, wetting agent, flavoring agent, etc were optimized by grade-consistency-test-method. Particle yield and angle of repose(fluidity) were used as evaluation indexes, optimal results of the formulation was validated. Parameters like critical relative humidity was determined by hygroscopicity test. RESULTS The best formulation of New Five-juice Decoction granules was:1.0 parts of dry extract powder, 1.0 parts of lactose and 1.0 parts of paclitaxel; soft material was made by 95% ethanol, wet granulation, drying under reduced pressure at 50℃ for 4 h. The kinetic equation of humidity absorption speed at different humidity meet the requirement of power function. The mathematical expression between time(Y) and environment relative humidity(X) at humidity absorption rate of 5% was Y=146.7-1.455 00X (R²=0.917 6, F=22.27, P=0.042 1). CONCLUSION Environment relative humidity should be controlled < 65% in production, the operating time when is exposed to the air should be controlled ≤ 48 h, in this condition the humidity absorption amount of New Five-juice Decoction granules can be controlled < 5%.