Abstract: Abstract Aerodynamic performance and aero acoustic characteristics of straight (un sweep)、forward sweep and backward sweep blade with different installed angles have been investigated experimentally under the take off condition.From their comparative study the following conclusions have been drawn.(1)An optimal prop fan design should be made by combining both high aerodynamic performace and low aerodynamic noise;(2)Blades with sweep have potentials for noise reduction;(3)Tip load reduction prop fan blade design would be benefit to lowering the noise level as well as to the prop fan efficiency improvement.