Abstract: For an air turbine with high loading,low rotational speed and greater torque output single-stage startup,aerodynamic analysis of prototype and aerodynamic modification design were conducted for achieving a more powerful shaft-power output.This turbine employed a centrifugal flow path,discrete nozzles and an impactive rotor.The flowfield analysis indicates that,this turbine has a very high loading coefficient,rather than a high adiabatic efficiency.Atechnical package was adopted in the modification design of increasing mass flow with almost the same turbine inlet total pressure.The flowfield simulation indicates that,when the rotor′s diameter is reduced to 94% of the original turbine,the power output of the modified turbine is about 2 times and 2.8 times of the original one at both the rotational speed of 100% and 140% of the original one.