In order to explore the influence of turbocharger volute inlet structure on the turbine blade excitation force, the turbine unsteady flow field model was established for calculation and analysis. The interference characteristics and excitation sources of turbine blade pressure induced by the asymmetric flow field of volute were analyzed emphatically. The scheme of excitation force weakening based on volute inlet structure optimization was further proposed and verified. Then the time and frequency domain characteristics of pressure fluctuation on turbine blade surface were analyzed. The results show that the non-axisymmetry of volute and the sealing effect of volute tongue affect the circumferential distribution of pressure in the volute flow field and the high static pressure area behind the volute tongue is the main cause of turbine blade excitation. The volute inlet structure affects the pressure peak in the high static pressure zone. The four proposed optimization schemes of inlet structure can reduce the excitation force of turbine blades on the premise of hardly affecting the turbine performance. Among them, Case 4 blade excitation amplitude decreases by 18.8%, which is the optimal scheme.