The tire cavity resonance noise has a decisive influence on the NVH performance of automobile. In order to study the noise reduction mechanism of the porous material on tire cavity resonance noise. Based on the tire force transmissibility，the consistency between the tire force transmissibility and the cavity noise is verified by experiments. A tire force transmissibility model is established and verified. The noise reduction mechanism of porous material on tire cavity resonance noise is studied through the tire force transmissibility model. The results show that the noise reduction effect of porous materials on tire cavity resonance is due to the coupling structural vibration and acoustic noise reduction. The physical and acoustic parameters of porous materials should be comprehensively considered when selecting porous materials. The research results provide an engineering application value for improving vehicle NVH performance and improving low noise tire design.