Based on the theory of infinite narrow grooves,the pressure distribution formula of liquid film lubricated noncontacting mechanical sealing with spiral grooves was derived,and the edge effect coefficient to the inlets and outlets of spiral grooves was modified.Parameters representing the liquid sealing performance,including bearing capacity,leakage rate and friction torque were calculated and verified.According to the characteristics of the liquid film seals with bidirectional combination of spiral grooves,a flow field computing method which based on weighted superposition theory was proposed.The flow field was calculated by choosing the staggered spiral groove as the example,and the calculation result was compared with that of Fluent simulation.The results show that the calculation method of edge effect coefficient is much more reasonable.The errors are in allowable range of engineering field between the method to calculate bidirectional combination groove flow field using weighted superposition theory and the method of Fluent simulation,which verifies the feasibility of the method of superposition,and provides reliable calculation method for engineering design and analysis.