Abstract: The influence of oil film thickness variation on workpiece gauge control in rolling process is analyzed. Based on the Reynolds' formula of oil film thickness by virtue of roll zeroing to calculate stand spring, the relative thickness of oil film is calculated, with the measured values obtained from data acquisition done on some plate mills. Neglecting the effect of stand spring and making curvilinear translation, the oil film thickness variation curve is given as a result by which the model structure and relevant parameters of oil film thickness can be easily determined. The workpiece gauge control precision at both acceleration and deceleration stages can be improved effectively by this model.