The triangular groove sealing structure for large cabin on a submersible was taken as the research object,the nonlinear finite element model of the contact between O-ring and triangular groove was established.The effects of rubber material hardness,O-ring inner diameter,chamfer and fillet of the groove of on the sealing performance of triangular groove sealing structure was simulated and analyzed.The results show that the rubber material hardness and the chamfer of groove have great influence on sealing performance,while the O-ring inner diameter and the fillet of groove have little effect on sealing performance.With the increase of rubber material hardness,the sealing performance is enhanced.However,under the same pressure,the greater of the rubber material hardness,the higher of the stress,which increases the possibility of damage of the O-ring.Therefore,under the premise of ensuring the sealing performance,the O-ring with lower hardness should be selected.With the increase of the chamfer size,the sealing performance and the stress of the O-ring decreases continuously.Therefore,under the premise of ensuring the sealing performance,it is necessary to select a larger chamfer size.