Power Line Communication(PLC) provides a low-cost data communication platform for automation system of electric distribution network. However，in PLC network，the characteristics of time-varying，high attenuation and high noise of the channel，have caused some problems like short distance of communication and poor reliability. It is quite difficult to resolve these problems at the physical layer，whereas they can be solved through the upper communication protocol. This paper proposes an adaptive routing algorithm，through which the routing among the nodes can be obtained，and the broken links can be repaired. The simulation results indicate that the algorithm is a simple and effective method of extending the communication distance and improving the reliability of PLC.