A turboexpander wheel, that is, turbine, is one of the critical components for a helium liquefaction plant. It helps to provide the cooling effect required for the liquefaction. The percentage of liquefaction depends upon the effective design of the turbine. The present work includes the design of a radial turbine for the intended power output of approximately 1.5 kW, with input conditions of 40-g/s mass flow rate at inlet, inlet total pressure of 14 bar, inlet temperature of 40 K, and outlet static pressure of 6 bar. The pressure values are taken to be absolute. Inlet conditions are selected on the basis of required refrigeration effect of approximately 1 kW. The outlet static pressure of 6 bar is maintained to avoid the turbulence, which may occur due to expansion for high pressure ratios. The present work involves the design and optimization of a turbine on the basis of the mean line analysis, initiating with the assumption of values for total-to-static efficiency. As per mean line design concept, a one-dimensional flow is considered for this analysis and the mean values of different parameters are considered at different sections. Losses are considered as the main constraint in design and it is desirable to get optimum net power. Besides, it is also desirable to achieve values for other design parameters in a specified range.