In the paper, to the patchwork problem of large chemical storage tank bottom, theoretical researches on arranging special-shaped parts are carried out. The heuristic layout algorithm with dynamic decision layout order and based on graphics position strategy is proposed. According to the algorithm, basing on Sinovation platform, using the objectoriented programming language C++ and Visual Studio tools, the arranging and patchwork system is designed and developed. And the application researches are made with the system. The results show that, comparing with the rectangular envelopment algorithm, the plate utilization ratio is increased with the patchwork algorithm proposed in the paper.