In order to analyze the contribution of operational vehicle interior noise sources, the responses near the noise sources are used as reference excitations. An operational vehicle interior noise transmissibility model is built, and the transmissibility test method is investigated. One problem is that the condition number of the reference excitation matrix changes with frequency. In light of this problem, a calculation method of the transmissibility matrix is put forward, then compared and validated with a heavy duty truck test, and the contribution of the truck′s interior noise sources is analyzed. The results show that the transmissibility model and transmissibility matrix calculation method can easily be applied to analyze the contribution of vehicle interior noise sources.