We develop a method to culculate the characteristics of supercavitating propeller making use of 2-D theories for partially cavitating and supercavitating wings. At first, we obtain the equivalent 2-D wing sections for the blade of a propeller operating in the noncavitating condition by using the quasivortex-lattice method (QCM). Then we apply 2-D cavitating wing theories to the equivalent 2-D wing sections and calculate the characteristics of supercavitating propellers by the concept of the wing element theory. Through comparisons between calculated results and experiments, we confirm the usefulness of this method.