The invention relates to a test device and a test method of performance of a screw drill motor. The test method of the performance of the screw drill motor includes: testing hydraulic characteristics of a rotor of the screw drill motor under external power drive according to a reversibility principle of positive displacement hydraulic machinery, and thereby simply, comprehensively and effectively testing and evaluating various performance indexes of the screw drill motor. The test device of the performance of the screw drill motor comprises a base seat, a drive unit arranged on one side of the base seat, a fixing unit arranged on the other side of the base seat and used to fix the screw drill motor to be tested, a water tank arranged on the outer side of the base seat, a circulating pipeline used to respectively communicate an outlet and an inlet of the screw drill motor with the water tank, a throttle control unit arranged on the circulating pipeline and used to control flow rate of the screw drill motor and a detection unit used to test various basic parameters of the screw drill motor, wherein an output end of the drive unit is connected with a rotor of the screw drill motor, and drives the rotor of the screw drill motor to rotate.