In order to achieve long distance transmission and obtain high communication quality， improve reliability and invulnerability of communication， an improved automatically dynamic routing algorithm for 10 kV power-line carrier communication is proposed. The algorithm is based on communication quality optimal theory and non-overlapping clustering-based routing algorithm. It combines with the corresponding communication protocol to implement the objective of automatic networking. Using the terminals of master and slave station of 10 kV power-line communication network as network nodes， it carries logic layer-built according to the communication mode， creates the initial routing table， optimizes the communication quality for routing table，updates and sets reconstruction strategy. Simulation of the algorithm with MATLAB and analysis of the communication quality and time-consuming are given. The simulation results show that the algorithm can achieve the automatic routing of medium-voltage power-line carrier communication and improve network reliability and invulnerability.