Aiming at the current situation of imperfect protection measures of turntables, a turntable protectionsystem based on ultrasonic ranging is designed. The basic working principle of the ultrasonic ranging is introduced.The hardware and software designs of the turntable protection system are described in detail. The testing is complet.ed in a laboratory. Testing results show that the system can trigger the alarm in time at the nearest presented dis.tance of 30 cm and the longest alarm distance of 70 cm, and the turntable's enable control button is cut off to ensurethe safety of testers. The feasibility of the ultrasonic ranging turntable protection system is verified, and technicalsupports are provided for other turntable protection designs.