As a result of manufacturing error,deflection moment and elastic deformation,the shaft journal may tilt in the bearing.Correspondingly,the bearing gas film thickness and pressure distribution will be changed,which has a significant impact on the bearing performance.In order to study the influence of journal misalignment on the bearing performance,the finite element perturbation method was used to solve the Reynolds equation,and the effects of journal misalignment angle and misalignment distance on the gas film thickness,pressure field,static and dynamic characteristics of the herringbone grooved gas bearing were studied.The influence of journal misalignment on the critical mass of the herringbone grooved journal bearing was also analyzed.The results indicate that the misalignment distance of shaft has greater influence on the static and dynamic performance of bearing,while the misalignment angle has less influence on the bearing performance.With the increase of deflection distance,the dimensionless bearing capacity and critical mass are decrease greatly,while the dimensionless friction moment declines slightly.