The arrangement design of ship cabin plan that satisfies most of crews and cabin passengers are apt to depend on making use of the experience and ingenuity of engineers and specialist during initial planning stage. It is desirable to be estabished the algorithm of arrangement design that is optimum in an overall perspective under a number of constraints. The process of optimum arrangement designing method in this paper is broken down into the calculation of initial optimum arrangement, zoning of rooms and optimizing room plan in each zone. An analytical method for optimum design is prosposed to use the sequential unconstrained minimizing technique (SUMT) as a crisp treatment way and the genetic algorithm as one way of solving the ill-defined problem. As typical example of applying the proposed method, the attempt about the simple geometrical arrangement and the cabin plan in a domestic vessel is carried out in order to clarify the justice of this methodology.