Abstract: In order to solve the poor load capacity of oil film bearings during the start-up process of tandem cold rolling mills, based on the hydrostatic bearing theory, a load bearing capacity model for oil film was established. The influences of screw-down tilting, hydraulic pump power and restrictor's hydraulic resistance on the hydrostatic pressure bearing-spindle system were calculated. The results show screw-down tilting is the basic reason of the problem. When there is an obliquity between the shaft sleeve and bush which is caused by screw-down tilting, the load capacity of the bearing drops suddenly. Minimizing the obliquity between the shaft sleeve and bush is essential to keep the kelmet working constantly. The results of calculation have already served as the guidance to make relative measures and achieved good effect.