Abstract.A dynamic integral sliding mode control (SMC) method for a class of mismatched nonlinear uncertain system is proposed in this paper. Based on the assumption of bounded uncertainties, a novel dynamic integral sliding mode surface is designed to overcome the inherent chattering problem of SMC. The gain of the proposed sliding mode surface is defined as an adaptive adjustment value, which could change the gain value according to the tracking error. By this way, the control system obtains an approaching rate proportional to the tracking error, thus weakening the chattering phenomenon effectively. Then the control law is designed to ensure the finite-time reachability of the closed loop system. Finally, numerical simulation is conducted to verity the validity of the proposed method.