The invention discloses a detecting tool and detecting method for a communication unit. The detecting tool comprises a casing, a communication unit interface is arranged on the casing; a control module, and a voltage current sampling module, a level timing analog detecting module, a serial port data transceiver module and a node simulator connected with the control module are arranged in the casing, the voltage current sampling module, the level timing analog detecting module, the serial port data transceiver module and the node simulator are also communicatively connected to the communicationunit through the communication unit interface. The invention also discloses a detecting method for the communication unit. According to the detecting tool and detecting method for a communication unit, the communication unit can be individually tested, so that the performance of the communication unit and the effective transmission of electric energy meter data can be guaranteed.