The invention discloses a power line carrier multistage networking test system based on distributed noise injection and wireless connection. The system comprises a central control unit, a plurality oflocal side test units, a plurality of meter side test units and a plurality of routing attenuator networks. The system is characterized in that the central control unit communicates with each test unit and the plurality of routing attenuator networks. The local side test unit is used for testing local side tested carrier equipment. The local side tested carrier equipment in the carrier communication network is used as a central node of the network. The meter end testing unit is used for testing meter end tested carrier equipment and serves as a relay node or a terminal node of a network. Therouting attenuator networks are used as carrier communication routes of the local side test units and the meter side test units. Each routing attenuator network can be connected with a plurality of test units; wherein each of the plurality of local side test units and the plurality of meter side test units is internally provided with a noise injection module. The noise injection module is coupledto a carrier interface of tested carrier equipment of the test unit.