Abstract: By introducing layer assignment algorithm, it can effectively optimize multiple important indicators such as delay and via counts in physical design, and then improve the chip performance. Therefore, a delay optimization layer assignment algorithm integrating multiple strategies is proposed, which considers both non-default-rule wire and coupling effect. First, aiming at the problem that the difference of nets is not carefully considered in the previous work, the differentiated net strategy is proposed. Second, in order to solve the problem of unreasonable evaluation of grid edge congestion in previous work, the segment classifying strategy is proposed. Third, aiming at the problem that the existing work pays more attention to consider congestion constraint when reassigning illegal nets, which leads to high delay of routing results, an effective reassignment and adjustment strategy is proposed. Finally, aiming at the problem of unreasonable routing order in the previous work, a variety of novel methods to determine the routing order are designed, and then a multi-objective driven sorting strategy is proposed. The algorithm runs in the Linux environment with a 2.60 GHz CPU and 64 GB of RAM. The validation experiments use the DAC12 circuit, and the experimental results show that the proposed algorithm can effectively optimize both delay and via counts without overflow.