Abstract: Due to the design difficulty of the rail pressure tracking control for high pressure common rail (HPCR) system, there is a shiver still in the equilibrium point of the system with the traditional sliding mode control resulted from its nature of discontinuous switching control and the method without consideration for the time-varying disturbance by fuel injection. To solve the system chattering problem, a new variable exponential sliding mode control (VESMC) method was proposed for HPCR system based on a nonlinear mathematical model established with the principle of fluid dynamics. A generalized proportional integral observer (GPIO) was designed to estimate the injection disturbance, and a VESMC method was proposed adapted to the GPIO. The results of simulation experiment associated with the software Matlab/Simulink and AMESim show that the VESMC method can increase the convergence rate by about 18.2% and reduce the chattering by about 40.8%. At the same time, after adding GPIO, the convergence rate can further increase up to 22.2% and the chattering can decrease to 39.2%.