The invention relates to a test method, a measurement device and a measurement method for the performance of a rotating drum differential of a finished automobile. The invention is characterized in that, by adopting the test method, a test vehicle is fixed on an automobile rotating drum testing table. The measurement device is installed on one side of a to-be-disassembled wheel. The rotating speeddifference of the wheel on the two sides is recorded. The rotating speed difference of the wheel of the test vehicle is increased, and then the traction force test of the vehicle is carried out. A controller compares the measured value with the traction force to serve as a differential performance evaluation index. The movable resistance brake pad of the measurement device is connected with an oil pressure piston rod. The oil pressure piston rod is driven by an oil injection motor. A pressure sensor is installed on an oil pressure cylinder. According to the measurement method, the measurementdevice is installed on the brake pad of an automobile, so that a fixed resistance brake pad and a movable resistance brake pad tightly clamp the brake pad of the automobile till the brake pad of theautomobile stops rotating. The pressure sensor detects the oil pressure. The function of the differential is examined under the condition that an actual road is simulated on the automobile rotating drum testing table. The test is not limited by a test site in a finished automobile state.