This bearing is composed of double-row balls in upper and lower layers separately, so it can simultaneously support axial force, radial force and tilting moment. In order to accommodate the different proportions among moments, the contact angle is in different value to 90°.When the diameter of the circles composed of distribution the two rows of balls is the same, Direct ratio between the total load capacity of each row of balls and the balls circle of distribution. Therefore, double-row ball slewing bearing can use the cross section size better when simultaneously supporting the radial force and tilting moment with the same support section.