A numerical method is presented for prediction of propeller performance and pressure distribution on blade surface according to lifting surface theory.The lifting surface model consists of two layers of constant strength quadrilateral vortex-ring elements covering both surfaces of the blades.The velocity jump across vortex sheet is included in the computation of the pressure distribution.The effect of blade drag has been included in the calculation of propeller performance.Numerical results agree well with experimental data for the considered two propellers.