Aiming at the problems of large error and low efficiency in cable laying based on traditional manual design, the computer-aided design optimized by ant colony algorithm is applied to cable laying path planning. The ant colony algorithm (ACA) is used to solve the shortest path problem of cable laying by taking advantage of the advantages of multi terminal line calculation in complex lines. At the same time, this paper planarizes the cable laying path, and further optimizes it by using Gompertz function from two aspects: pheromone restriction and self-adaptive adjustment of volatilization factor, which improves the convergence speed and global performance of ant colony algorithm. The simulation results show that the optimized ant colony algorithm can quickly get the shortest cable laying path in the process of substation digital three-dimensional cable laying, save the cost of manpower and materials, and improve the design accuracy.