In order to solve the problems of the traditional spiral groove dry gas seal in reverse rotation,such as poor dynamic pressure effect,easy to wear and instability,a new type of bidirectional rotary tree-shaped groove was proposed.SolidWorks software was used to establish the three-dimensional model of gas film,ICEM software was used to divide the grid,and Fluent software was used to simulate the flow field.The opening force and leakage rate of bidirectional rotary tree-shaped groove under different film thickness,groove depth,speed and other parameters were compared with those of the spiral groove.The results show that the tree-like groove can produce obvious dynamic pressure effect and has larger opening force,its leakage rate is higher compared with the spiral groove.When the film thickness is 2 μm and the groove depth is 5 μm to 7 μm,the tree-like groove has better sealing performance.The film thickness and groove depth have a great influence on the sealing performance.The opening force of dry gas seal decreases with the increase of film thickness and increases with the increase of groove depth.The opening force of the two grooves increases with the increase of pressure and speed,but compared with the spiral groove,the sealing performance of the tree-like groove is less affected by the rotation speed and it has a better opening effect.The tree-like groove has good sealing performance while realizing bidirectional rotation,which provides a certain reference for the design of bidirectional rotary dry gas sealing groove.