Abstract: The aerodynamic design of tilt-rotor must be synthetically considered to meet the different requirements between helicopter mode and airplane mode,thus the blade’s aerodynamic parameters need to be optimized so that the tilt-rotor has higher hover figure of merit and cruise propulsive efficiency.In this paper,the aerodynamic performance analysis model of tilt-rotor has been built on the free-wake theory,the hover figure of merit and cruise propulsive efficiency are selected as the design objective,the chord distribution,pre-twist distribution,rotor thickness,airfoil-station distribution and rotor speed of blade are selected as design variables,the rotor power and blade weight are selected as constrains,the multi-objective collaborative optimization technique is used to deal with the aerodynamic multi-objective optimization design problem,the rotor has better aerodynamic performance after optimization,and computation results indicate the optimization method is feasible.