Basedontheobservationofthemeso-structureof2.5Dbraidedcomposites,athree-dimensionalmechanical modelispresented,whichismorestableandisabletoreflectthestructureofthiscomposites.Therelationshipbetweenthe fibervolumeandgeometricparametersisdeducedbyusingthismodel.Thestiffnessaveragemethod(SAM)andfiniteelementmethod(FEM)areadoptedtopredicttheeffectivemechanicalproperties.Theelasticconstantsvaryingwiththechange offibervolume,warpdensityandweftdensityareanalyzed.Bothofthepredictedresultsshowthecamberangledoesnot noticeablyaffecttheelasticproperties,buthasanotableimpactonthemeso-stressfield.ThetheoreticalpredictionisinaccordancewiththeFEMresults,whichverifiesthevalidityofthemodel