Contours of surface texture of contact faces are not always parallel to the directions of the axis in solving Reynolds equations with finite difference method, and this often induces significant pressure saw-tooth effect, which results in an unignored analysis error. In this paper, pseudo-nine-point finite difference, as a new finite difference method, is introduced to solve the lubrication numerical problem of pressure saw-tooth. Also, application is carried out in gas lubrication of hard disk systems to verify the validity of the new method. In analysis, pressure distributions and gas floating forces are calculated for two different types of sliders, and the astringency and efficiency of the new method is discussed. Numerical results show that the pseudo-nine-point finite difference method can restrain pressure saw-tooth evidently, and presents better astringency and efficiency than the traditional five-point finite difference method. With the increase in mesh density, pressure distribution and gas floating force trend to steady. Also, numerical values of the floating force agree well with the experimental ones.