To explore the influence mechanism of the detailed design parameters of volute on the distribution and variation of flow at rotor inlet and improve the turbine efficiency under pulsating flow, the effects of volute outlet radius, volute section shape and inlet duct angle on the turbine flow characteristics were studied by using three-dimensional unsteady numerical method. The results show that the increase of volute outlet radius can effectively suppress the circumferential distortion caused by the volute tongue. In addition, the entropy generation rate on the blade suction surface near the volute tongue and on the pressure surface of the blade reduce respectively at the pulse peak and trough and hence the turbine aerodynamic performance improves. The pear-shaped volute is superior to the circular volute, which reduces the entropy generation rate at the volute tongue. The inlet duct angle mainly affects the gas flow at the volute tongue. The increase of duct angle enhances the flow distortion at the volute tongue, and increases the equivalent A/R ratio and MFP of volute.