The dewetting of ultrathin liquid films in the presence of insoluble surfactant monolayer was studied.Under slip boundary conditions，coupled nonlinear evolution equations for film thickness and surfactant concentration based on lubrication theory were used.The dewetting evolution of films was simulated using PDECOL program，and the effects of slip length on dewetting dynamics，including endogenous and exogenous surfactant cases were investigated.Numerical results showed that the impact of slip boundary on dewetting process was closely related to initial surfactant distribution，and was obviously different under various equilibrium film thicknesses.Slip boundary generally played a role of improving the stability of ultrathin insoluble surfactant-covered films，and especially for small equilibrium film thickness，slip boundary could restrain the dewetting processes effectively.For spinodally stable films，the effect of slip boundary on exogenous surfactant dewetting was more noticeable than that on endogenous surfactant case.