Affected by the full traversal environment, the paths planned by existing methods are too long. For this reason, this study proposes a planning method for the full traversal path of omnidirectional mobile robots based on an improved ant colony algorithm, hoping to improve the path planning and obtain the optimal path. On the basis of the topological modeling diagram, a new environment model is established by angle conversion according to the position information of a mobile robot in the original coordinate system. Considering the problems in the ant colony algorithm, the decreasing coefficient is introduced into the heuristic function to update the local pheromone, and an iterative threshold is set to adjust the volatility coefficient of pheromone. Finally, the path planning process is designed to plan the full traversal path. The results show that the proposed method can shorten not only the full traversal path but also the planning time to obtain the optimal path, thereby improving the planning for the full traversal path of omnidirectional mobile robots.