The area ratio selection and nozzle contour design are important tasks. In this paper，the two-dimensional optimization technique is used to optimize area ratio and nozzle contour by means of the program of computation of two-phase nozzle flow and direct optimization techniques. It is shown that the area ratio of thrust maximum considering two-dimensional two-phase loss is much smaller than the theorectical optimum area ratio，and it is greater than that of impulse-weight ratio maximum for conical nozzle，and it is just a little greater than that one for contour nozzle，and the optimization contour is the optimization contour under optimum area ratio for contour nozzle.