The invention relates to a detection device for the quality of power carrier signals. The detection device comprises an electrical source, N signal quality detectors and an intelligent control server, wherein the electrical source is used for inputting current into a power line and providing working voltage; the signal quality detectors are connected with the power line; N signal quality detectors send coaxial signals to the next-level signal quality detector; the signal quality detector can generate signal quality information if acquiring the coaxial signals sent from the upper-level signal quality detector; the first-level signal detector in N signal quality detectors acquires the power carrier signals from the power line and converts the power carrier signals into the coaxial signals; N signal quality detectors generate M signal quality information according to the coaxial signals, wherein M is more than 0 and less than or equal to N; the intelligent control server is used for acquiring M signal quality information and generating a maximum relaying number according to m signal quality information. The detection device can simulate the operation condition of the site and finish the performance testing of quality and relaying of the carrier signals of the power line under the laboratory environment in an automatic and high-efficiency manner.