In order to study the dynamic sealing performance of large-size O-shaped rubber seal ring,a dynamic sealing performance test platform for large-size O-shaped rubber was developed,and the dynamic sealing performance of O-shaped rubber seal ring was tested at the pressure from 15 kPa to 600 kPa under the condition of water medium.Based on orthogonal experimental design,the dynamic sealing performances of nitrile rubber seal ring with inner diameter of 600 mm (section diameter of 10 mm) under different medium pressure,compression (from 075 mm to 125 mm) and rotating speed (from 5 r/min to 50 r/min) were studied.The results show that the leakage of the seal ring increases approximately linearly with the increase of water medium pressure,decreases slightly with the increase of compression,and is basically constant with the increase of rotating speed.The end face friction torque increases linearly with the increase of water medium pressure,and changes little with the increase of rotating speed and compression.Among the three factors of medium pressure,compression and speed,the medium pressure has the greatest influence on the leakage,followed by compression and speed.The medium pressure has the greatest influence on the end face friction torque,followed by speed and compression.