Abstract: Since 1979, prof. F. V. Chang of Tsing Hua University has obtained, by the method of superposition, a series analytic solutions for cantilever rectangu lar plates under uniform load and some cases of concentrated loads. In this paper, the problem of bending of cantilever rectangular plates under hydrostatic pressure is solved by the method of two-direction trigonometric series instead of the method of superposition. The application of the pre sent method to the bending of rectangular plates underany distributed surface-load is explained.