The utility model relates to a novel ammeter terminal box for anti -electricity -stealing, including casing, upper cover and inside detection circuitry, its technical characterstic lies in: this detection circuitry is connected with the misconnection line blocked mechanical system who installs in the casing, misconnection line blocked mechanical system includes step motor, cam and fore -set, stepmotor installs on the circuit board, and is connected with detection circuitry, this step motor's transmission shaft with the cam is connected, and contact in this cam top and be connected with the fore -set, the fore -set can be installed in the track through -hole with reciprocating, and this track through -hole lies in in the lateral wall of ammeter terminal box, with casing an organic whole ismade, when detection circuitry control stepper motor drive cam is anticlockwise swung, the fore -set can upwards stretch out the casing, when the detection circuitry control stepper motor drives theswing of cam up time needle the fore -set can be return downwards to the casing in. The utility model discloses the user can be stopped and the electric action of stealing of terminal box and electricenergy meter is utilized.