Multi-leaf hydrodynamic gas journal bearing is widely used in high-speed centrifugal separator,air compressors,turboexpander and other rotating machinery due to its simple structure,low friction resistance and pollution-free.In order to explore the static performance of multi-leaf hydrodynamic gas journal bearing,the Reynolds equation of three-leaf hydrodynamic bearing was transformed into the standard partial differential equation through mathematical transformation,and was solved by finite difference method and over-relaxation iterative method.The variation of static performance such as gas film thickness and pressure distribution,load carrying capacity,friction coefficient and mass flow rate with eccentricity ratio,preload factor,bearing number,length-to-diameter ratio and pad distribution position was studied.The results show that the load carrying capacity and friction coefficient of the journal surface of three-leaf gas bearing increase with the increase of eccentricity ratio and length-to-diameter ratio,while the attitude angle and mass flow rate exhibit opposite trend with the increase of eccentricity ratio and preload factor.As the bearing number and preload factor increase,the bearing capacity and friction coefficient significantly increase,while the attitude angle and mass flow rate gradually decrease.The distribution position of tiles has a significant impact on the static performance of three-leaf gas bearing,the load carrying capacity,mass flow rate and attitude angle of load on pad are significantly higher than those of load between pad.