The mechanical energy of the turbine output of the micro turbine generator has an influence on the energy utilization rate of the pressure gas at the exhaust side of the cylinder. Therefore, increasing the output torque of turbine is the key method to improve the efficiency of turbo generator. In order to analyze the influence of inlet position and volute structure on turbine output torque, a theoretical model of turbine force and torque was established. The validity of the theoretical model was verified by experiment and simulation analysis. The influence of different inlet position and volute structure on turbine output torque was deeply studied. Then a turbine producing large torque and small influence on the exhaust characteristics of the cylinder was designed.It lays foundation for the effective integration of micro turbine power generation system.