The invention discloses a resistance simulating mechanism of a vehicle electric power steering system test bench, which aims to overcome the problem of extremely high cost, low testing accuracy and hydraulic fluid leakage and the like. The invention comprises a car model (1), a motor controller (2), a decelerator (3), a resistance simulation executive motor (4), a resistance simulation steering device (5) and a thrust transducer (6). The power supply input end of the resistance simulation executive motor (4) is connected with a wire output end of the motor controller (2), an output shaft of the resistance simulation executive motor (4) is connected with an input shaft of the decelerator (3), an output shaft of the decelerator (3) is fixedly connected with the input end of the resistance simulation steering device (5), the output end of the resistance simulation steering device (5) is fixedly connected with one end of the thrust transducer (6), the other end of the thrust transducer (6) is fixedly connected with the input end of an electric power-assisted steering system (7) for measuring, and a signal output end of the thrust transducer (6) is connected with a signal input end of the motor controller (2).