This paper aims to investigate the effect of porosity percentage on the wear performance of a wet clutch. A wear calculation model for the relationship of porosity and wear mass loss is established. The results of experiments conducted verify the wear coefficient expression used in the model. The influence of porosity on the wear performance of a friction disc was also analyzed for various pressures and speeds. Specifically, the 80 min sliding test was performed with three different friction disc porosity percentages using a wet clutch test rig. Comparison of the model calculation results with the measured values confirmed the accuracy of the calculation model. The test results show that the calculated and detected data fit well, which indicates that the wear calculation model can be used to estimate the wear mass loss of wet clutch friction plates. These research results will help to improve the anti-abrasion properties and employment lifespan of wet clutch friction discs.