The invention relates to the technical field of machinery, and particularly relates to a bearing of a large rotary platform truck. The bearing comprises a pair of corresponding bearing retaining rings and steel balls between the two bearing retaining rings, wherein a circular groove convenient for the steel balls to roll is formed in the middle of each of the bearing retaining rings, a plurality of steel balls are uniformly distributed in the circular grooves, a steel ball isolating column capable of sliding in the circular groove is arranged between each two adjacent steel balls, and the diameter of each steel ball isolating column is less than that of each steel ball. According to the invention, the steel ball isolating columns with proper size are used for isolating the steel balls, thereby alleviating the self-wear of the steel balls and prolonging the service life of the bearing; to be specific, the polytetrafluoroethylene steel ball isolating columns are adopted to ensure smooth rolling of the steel balls and have a certain lubricating effect on the steel balls, thereby satisfying the production requirements and solving the production problems.