Abstract: Relationship between water content of Amomum tsaoko and permittivity，dielectric loss，loss angle tangent and penetration depth was studied by TG-DTG and dielectric parameter test system.Research results showed that thermal weight loss process of Amomum tsaoko was divided into free water removal stage and bound water removal stage.When free water exists of Amomum tsaoko，dielectric constant and dielectric loss decreased slowly.While as Amomum tsaoko was only bound with water，dielectric constant and dielectric loss decreased rapidly.Plots of nonlinear surface fitting indicated that penetration depth increasing with water content descent of Amomum tsaoko.There was exponential relationship y=Ae-ax+y0 between penetration depth and water content.