Mechanical property of 3-D braided composites is closely related with braiding parameters.In order to study the bending performance of carbon fiber braided composite gears and its relationship with braiding parameters,a prediction model of composites and gears bending performance was proposed.Based on the representative volume cell method and the idea of homogenization,a mesoscopic and macroscopic model of composites was established.The volume average method and the finite element method were used to predict the bending performance of composites and gears.In addition,two pairs of carbon fiber braided composite gears were prepared by four-step braiding and compression molding methods,and the bending performance of the composites and the gears under specific braiding parameters was obtained through experiments.The prediction results are in good agreement with the test results,which verifies the accuracy of the prediction model.Finally,the bending performance of composites and gears was predicted under multiple sets of braiding parameters,and the influence of braided angle and fiber volume fraction on the bending performance of composites and gears was obtained,and the braiding parameters that made the bending performance of composite gears to be the best were given