Objective: To study moisture dynamics modelof raw materials of Chinese materia medica through mathematical simulation

and analyze hygroscopic properties of raw materials of Chinese materia medica from view of dynamics. Method: Water absorption of raw materials of Chinese materia medica was determined

Fick'sfirst(second) diffusion law

First-order asymptotic model and Peleg model wereadopted to simulate water absorption kinetics of Chinese medicine raw materials. Result: Moisture absorbing of Chinese medicine raw materials fitted Fick diffusion law

several models were used to imitate moisture absorbing and Peleg model was better than others model

model was relative with equilibrium moisture content and initial rate of water absorption.Similarities between predicted and actual values of Lanqin

Shuanghuanglian prescription

Shanjun Jiangya prescription

Lemai prescription

Xuanmai Ganju prescription

wild chrysanthemum

Chuanshen prescription

Kangxinning prescription

Anshen Yangxin prescription extract were 0.999 6

0.995 9

0.999 2

0.927 1

0.995 7

0.998 8

0.999 1

0.919 8

0.979 6

diffusion coefficients were 1.16×10-7

1.74×10-3

3.06×10-3

2.62×10-3

2.16×10-3

2.48×10-3

2.23×10-3

2.85×10-3

2.64×10-3

respectively. Conclusion: Hygroscopic mechanism of Chinese medicine raw materialscould be explained by investigating absorption kinetics with mathematical simulation.