The invention provides a servo system rotation clearance simulation device which comprises a coaxial fixing rod, a wheel disc coupling, a coupling fastening screw, a fixed-angle wheel disc, a rotary sliding block, locking nuts, adjusting screws, a fixed-angle feeler gauge, a coaxial washer, a spring washer and a fastening screw. The wheel disc coupling, the rotary sliding block and fixed-angle wheel disc are arranged in order with the rotary sliding block in the middle. The coaxial fixing rod penetrates through a round hole in the middle of the wheel disc coupling and a round hole in the middle of the fixed-angle wheel disc and is fixed to the coaxial washer, the spring washer and the fastening screw through threaded connection. The coupling fastening screw is installed on the wheel disc coupling, the locking nuts and the adjusting screws are installed on the fixed-angle wheel disc, and the fixed-angle feeler gauge is inserted into a position space of the fixed-angle wheel disc. The servo system rotation clearance simulation device is simple in structure, convenient to install and low in cost, and has the value of promotion and application.