An unsteady numerical simulation of the transonic flow of a full-circumferential blades of contra-rotating propfans was carried out by using the immersed body-fitted grids boundary method and the developed CFD program. The flow chart of this program

grid generation strategy and flow solver principle were introduced.The influence of unsteady interaction of tip and wake vortexes on the front and rear rotors was analyzed.The unsteady fluctuations of the thrust

power and propulsion efficiency of the contra-rotating propfans were calculated and compared with the corresponding results of NUMECA simulation. The difference between thrust and efficiency of the rear rotor simulated by those programs was more than 10%. Compared with NUMECA’s single channel steady simulation of contra-rotating propfans

the proposed method and program had more accurate simulation results and extremely convenient grid construction when using the the same order of total grids number.