Abstract: Based on the service conditions and working principle of a compliant floating ring gas cylinder seal,the key-points of the seal design and analysis were studied and the numerical calculation model was established on rotating reference frame. A quasi-dynamic characteristics analysis method was presented and the seal performance was analyzed quantitatively. Static characteristics of the seal and mechanical characteristics of the gas film were calculated through finite element method. According to the typical service conditions in counter-rotating shafts,the relationship of the seal performance parameters and the film thickness was obtained through numerical analysis and simulation.