In order to investigate the changes in rock cutting force and wear of disc cutters under sliding states, a rolling circumferential cutting model considering both the rotation of hob and the revolution of disc cutters is established based on the discrete element method. A slip ratio parameter η is defined to describe the sliding state of disc cutters. The force and wear of disc cutters are compared and analyzed under different slip rates η, and the numerical simulation conclusion is verified with an engineering example. The results show that the vertical force FV and rolling force FR in the numerical simulation fluctuate near the calculated value of CSM model, which are in good agreement, indicating the rationality of the model in this paper. The numerical simulation results show that with the increase of slip ratio η, the vertical force FV decreases slightly and the rolling force FR increases significantly. From cutting rock in rolling state to cutting rock in sliding state, the vertical force FV decreases by 23.6% and the rolling force FR increases by 83.7%, indicating that cutting rock under sliding state will lead to flat wear of disc cutters. The engineering data show that the increase of thrust is the main manifestation of a large number of disc cutters in the normal wear. When a large number of cutters are in flat wear, the main mainfestation is the increase of torque. Specifically, when the proportion of flat wear cutters is 19.05% and 28.57%, the increase of torque is 55.85% and 261.51% respectively. When there are a large number of normal wear and eccentric wear of cutters, the torque and thrust increase synchronously. The torque increases by 80.89% when the flat wear of cutters accounts for 21.43%. The numerical simulation and measured data show a high level of consistency. Based on the results of four opening, the increase of cutterhead torque by more than 50% can be used as an important basis for determining the flat wear of a large number of cutters.