Plastic model sand has been widely used in channel physical model tests as one of the critical materials.The accuracy of its physical properties is imperative for parameter setting and result analysis.Dry bulk density,which directly affects the results of physical model calculation results and analysis of river bed scour and silt,is a vital physical index of model sand gravity features.This study analyzes the traditional cutting ring method and measuring cylinder method for dry bulk density measurement and proposes improvement measures according to test data,achieving better accuracy and stability of test results.The improved cutting ring method and measuring cylinder method are innovative and have been verified by experiments,which can provide guidance and basis for the plastic model sand test in related industries.