An electronic waste-gated turbocharger for automotive application can accurately control the boost pressure and can also effectively reduce the turbo-lag. It improve the transient responsive performance of engine and the acceleration performance, which make vehicle have a better adaptation to the complex traffic environment. A detail analysis of aerodynamic working principle is the foundation for the optimal control strategy of electronic waste-gated turbocharger. The study, in which the influence of the valve opening on the performances of electronic waste-gated turbocharger turbine under the condition having periodic pulse exhaust gas of engine, has the practical application value. This paper discusses the unsteady performances and mass flow characteristics of a turbocharger turbine with an electronic waste-gate under different valve opening conditions using numerical simulation method, based on a unified periodic pulse inlet wave. The influences of the valve opening on the performances of electronic waste-gated turbocharger turbine are researched detailly from fully opened to fully closed under pulse condition, and as a reference, the steady is also presented here. The results show that the nearer the valve opening approximates to full close, the greater is the influence on the turbine unsteady performances, and the bigger is the flow loss in every unit of degree. The flow loss in the turbine and the bypass is evaluated, and the mechanism of the inﬂuences is explored by flow field and statistics analysis. This paper be good for a better comprehension of the actual working in the bypass, and can also be helpful to the structure optimizing and the control strategy design of the electronic waste-gate.