Abstract: The sound absorption coefficient of the inner soundproof pad of a certain automobile dash panel is measured by using the reverberation room method, and the influence rules of test-piece arrangement, acoustic source position and microphone layout on measurement results are probed into. Results show that all the three factors generate obvious influences on the results at low frequencies, whereas almost no influences on the results at medium-high frequencies. Consequently, in order to obtain the sound absorption coefficient accurately, it is necessary to consider as many configurations as possible and average the results of all the configurations. The average sound absorption coefficient of the inner soundproof pad is about 0.45. Further, its insertion loss is measured and its primary acoustic weak links are identified based on the reverberation-room and anechoic-room method with sound intensity testing. Results show that the average insertion loss of the inner soundproof pad is about 12 dB, and the primary sound isolation weak links are the mounting positions of the steering mechanism, the A/C blower and the steering gear's dust cover. This study will provide not only a basis for the analysis and improvement of this inner soundproof pad's acoustic properties but also guidance for the acoustical materials' property test.