In the investigation,the diagonal rooms within a residence building are disassembled into a variety of subsystems,and the sound energy equations of the diagonal room system are set up.By solving these equations,the overall sound pressure level difference and the sound pressure level differences along each sound transmission path are predicted.Then,through the dominant sound transmission path,the parts of weak sound insulation performance within the diagonal rooms are determined,and a sound insulation prediction model is constructed.The theoretical prediction indicates that,in the whole frequency range,the dominant sound transmission path of the diagonal rooms is the flanking sound transmission path that passes through the floor wholly,and that,in the frequency range of 200 ～ 500Hz,the separating wall of lightweight material is prone to ameliorate the sound insulation between the diagonal rooms.In addition,as the developed sound insulation prediction model involves the first-and second-order flanking sound transmissions,the prediction values of the sound pressure level difference are reduced by 3 ～5dB,thus the prediction precision of the sound transmission in the diagonal rooms is improved.Therefore,the prediction model can be adopted to seek effective approaches to improving the sound insulation of a residence building.