Abstract: In the grinding process of roll grinder,chatter marks are easily to be found on the surface of the roller,which is harmful to the production efficiency and quality. There may be lots of reasons to chatter marks,among which grinding wheel dynamic imbalance was chosen to structure the roll grinder dynamic model based on doubly regenerative time delay grinding model. Runge-kutta algorithm was used to solve the model and the dynamic characteristics of grinding wheel dynamic system were derived. Various simulation results of different degrees of grinding wheel dynamic imbalance are calculated,which coincides with the experimental data,and then the roll grinder dynamic model was demonstrated to be proper and valid.