Abstract: In order to meet the need of high-precision design of electric spindle of precision grinding machine, static and static bearings are used as support bearings, and the structure of static and static bearings is small orifice restrictor with four oil cavities. The structure and operating conditions of the bearings are analyzed, the theoretical calculation method of the static and dynamic characteristics of the bearings is given, and the influence of the throttle aperture d and the oil cavity area A on the static and dynamic characteristics is analyzed. The static characteristics include the bearing capacity F and the flow rate Q, and the dynamic characteristics include the stiffness coefficient k and the damping coefficient c. The results show that with the increase of d, F first increases and then decreases, and reaches the maximum value when d is 0.5 mm. Q increases with the increase of d, and the increasing trend becomes slower. F increases linearly with the increase of A, and begins to decrease when A is greater than 1 000 mm². Q increases with the increase of A, but the increasing trend shows an increasing sign. The principal stiffness k_xx firstly increases and then decreases with the increase of d, and reaches the maximum value when d is 0.5 mm. k_yy decreases with the increase of diameter, but the decreasing trend slows down after d is 0.5 mm. With the increase of A, the principal stiffness k_xx and k_yy in both directions increase approximately linearly, and k_xx reaches the maximum value when A is greater than 1 000 mm². The cross-stiffness k_xx decreases with the increase of A, but the decreasing trend is gradually gradual.