Transmission loss (ATF or PPNR) is generally used as a method of evaluating vehicle sound insulation performance. But since transmission loss evaluation is conducted in a stopped state, it is difficult to reflect the characteristics of noise generated during driving, and it is difficult to determine how much each interior trim contributes to interior noise reduction. In order to develop optimal vehicle sound insulation performance, it is necessary to identify major panels that contribute to interior noise under driving conditions (acceleration/constant speed) and to develop an integrated sound insulation performance index that quantifies the degree to which interior trims contribute to interior noise reduction. Using this integrated sound insulation performance index, it will be possible to develop an interior trim that can realize good sound insulation performance while considering cost/weight. For developing an integrated sound insulation performance index for each driving condition in this study, Panel Contribution Analysis (PCA) was conducted on interior noise under actual vehicle conditions and bare conditions.