Abstract: The power line communication detection device is the core equipment of the energy Internet for low-carbon buildings. Although the transmission speed of power line communication（PLC）used in the device is fast,its path search signaling communication reliability is low, which seriously restricts the improvement effect of the relay means on communication performance. The reliability of two way automatic communication system（TWACS）is high,but its path search speed is slow,which seriously affects the timeliness of communication. To improve the performance of the PLC detection devices applied in energy Internet information perception,an improved path search algorithm of multimodal integration of power line communication using the abovementioned PLC and TWACS is proposed in this paper. In order to ensure the communication coverage,The PLC is mainly responsible for data information transmission, while its downlink communication search signaling is replaced by the strong-robustness TWACS to ensure the reliability of broadcast information and path relay command transmission. The simulation results indicate that the proposed algorithm can effectively improve the communication quality and efficiency of the power distribution network, and meet the performance requirements of power line communication detection devices in low-carbon buildings better.