In this paper the authors study the improvement method of cavitation characteristics of MAU type propeller. The “two-dimensional cavitation bucket chart” which was developed by Gutsche, Nakajima, Ito, etc., is insufficient to predict cavitation of a propeller because it is originally based on two-dimensional sections. The authors proposed a new chart, “three-dimensional cavitation bucket chart” by using Koyama's lifting surface theory of a propeller and the concept of two-dimensional corresponding section. The theoretical pressure distribution calculated by the above mentioned theory, agrees with experimental results, measured on a model blade in uniform flow. Calculations in non-uniform flow were also carried out by using Koyama's unsteady lifting surface theory. The results were compared with the three dimensional cavitation bucket chart. It was found out that the unsteady effect was not large and the three dimensional cavitation bucket chart is also useful for the prediction of cavitation of a propeller in ship wake.