Abstract: The layout design of ship cabins is a complex process that requires much manpower and time resource, and the 3D modeling software and the drawing software are still playing major roles in the computer aided ship design. In order to instill the ability to output the design automatically and thus improve the efficiency of layout design of ship cabins, a method for layout design of ship cabins on multi-decks is proposed. Firstly, based on the design specification, statistical laws, and design experience, a mathematical model with four objective functions is given by analyzing requirements for the layout design of ship cabins, which includes the environmental factors, accessibility, weight distribution, and area functions. Then, the Gravitational Search Algorithm (GSA) is used in the mathematical model to complete the design module. The results of the validation test show that the design requirements are well met, which proves the rationality of the method.