Abstract: In response to the needs of intelligent production line CNC machining center, a electrospindle support bearing was designed, the design bearing is a four-cavity hydrostatic plain bearing, and the core design parameters include inner diameter, oil sealing surface width, oil return groove width, throttle ratio and radius clearance. A calculation model of the support stiffness of hydrostatic bearings was established, and the stiffness value of the design bearing at a load of 100 ~ 700 N was calculated to be 6.0×10⁷ ~ 10.2×10⁷ N/m. The effects of oil sealing surface width, oil return groove width, throttle ratio and radius clearance on stiffness were analyzed, and the bearing design parameters were optimized, and the stiffness value of the optimized bearing was 11.4 ~ 29.8×10⁷ N/m. The static stiffness test of the bearing was carried out, and the horizontal stiffness was 3.1×10⁷ ~ 25×10⁷ N/m and the vertical stiffness was 2.5×10⁷ ~ 23×10⁷ N/m when the load was 100~700 N. The results show that the width of the oil sealing surface and the clearance of the radius have a great influence on the stiffness of hydrostatic bearings and are important design parameters. The stiffness test test value is smaller than the theoretical calculation value, which may be caused by manufacturing and assembly errors caused by the performance of bearing throttle, oil cavity and other structures being more sensitive to dimensional errors.