Abstract: The optimization of two-dimensional irregular object layout is a basic problem in computer science and operational research, and has found key applications in many industries, such as VLSI manufacturing, ship-building, sheet metal and clothing, etc. But the current results from traditional methods do not satisfy real applications. In this paper, a genetic algorithm about this problem is proposed and implemented, and then applied to an apparel CAD system. Firstly a formal description of the problem is proposed, and then the problem is transformed into one kind of equivalent form about polygon motion planning. Three genetic operators are also designed according to characteristics of the problem, and the algorithm adopts current optimal algorithms about polygon motion planning in decoding and evaluating candidate solutions. Experimental result shows that the proposed algorithm is good at solving the layout problem.