This paper expounds importance and complexity of power line carrier communication(PLC). Test simulation system is established for low voltage PLC by distributed mode. This system breaks through the existing concept of centralized test, reflect the actual running condition, and test the parameters of low voltage PLC. Distributed architecture is characteristics of the simulation system. Not only performance indicators can be tested, but also routing structure and received signal quality of the electric power net. Real environment laboratory is established to imitate PLC scenes of various operating conditions through impedance matching. Regular changing of routing and received signal quality of PLC can be mastered. This test simulation system can provide a scientific basis for inspecting PLC system and quality of PLC products.