Amathematicalmodelwasdeveloped toanalyzethe characteristics of the wet clutch duringengagement. The lubricantsqueeze actionwassimulatedwithPatir and Chengaverage flow model in which thepermeabilityof frictionmaterialis takeninto account, andtheasperityloadis calculated according totheGreenwoodandTrippapproach. In thismodel,effects of friction materialpermeability, applied load and driving velocity on the engagement characteristicsofthewet clutchwerestudied. Theresults show that friction material with high permeability reducesthe film thickness rapidly and increasesthe torque peak;the applied load increases the asperity contact pressure and the friction torque,andreduces the engagement time;the driving velocity mainly increases the engagement time.The theoreticaltorque and relative velocitycurvesagreequalitatively with the experimental ones,whichverifiesthe wet clutch engagement model.