In this research, the aerodynamic design of a radial inflow turbine impeller is carried out using a direct design Method.This new method consists of 2 steps; one dimensional design and three dimensional design. In this design, the blade 3D geometry is obtained with new method. Moreover flow properties in various blade points can be investigated. The advantages this method in comparison with previous other method is less time & cost consuming and more accuracy. At the first step of the aerodynamic design, 1D design is done. This program’s inputs consists of; stagnation temperature, stagnation pressure, mass flow rate and pressure ratio. The goal of 1-d design is to obtain according to optimum experimental data. This procedure based on impeller efficiency convergence. At the second part of this research, by developing a novel design method, the 3D profiles of blade and impellers will be obtained. To validate of one dimensional design results, experimental results and for three dimensional designs, Computational fluid dynamic (CFD) analysis is used. In all this steps, good agreement is observed.