Sheet metal parts occupy an important position in the manufacturing industry due to their advantages such as light weight, high strength, low cost, mass production and good performance. In order to shorten the production cycle and improve the utilization rate of materials, parts of the same material with the same thickness are usually arranged on the same board for one time. The optimization algorithm of layout is studied in this paper. The convex package of the polygon is solved by the volume wrapping method, and the minimum envelope rectangle of the part is obtained. A mathematical model of rectangular parts layout is established. By comparing the positioning method of the lower step method, the minimum horizontal line method and the residual rectangle method, a minimum horizontal line method is designed as a positioning rule. According to the characteristics of the layout problem of rectangular parts, a layout ordering rule is designed with the theory of genetic algorithm. This optimization method is implemented by using Matlab software to verify the feasibility.