Abstract: In order to solve path planning problem of coal exploration and rescue robots in three-dimentional environment, an optimal path planning method for coal exploration and rescue robot based on improved ant colony algorithm was proposed. Three-dimensional space environment model is established by using grid method, and path planning objective function of coal exploration and rescue robot is established. Node transition probability design, node selection strategy and pheromone update strategy are optimized and improved by introducing new heuristic function factor, random selection mechanism of node and combining strategy of local updating and global updating. Matlab simulation results show that both the traditional ant colony algorithm and the improved ant colony algorithm can find an optimal path for the coal exploration and rescue robot in the three-dimensional environment model. Under different task requirements, the improved ant colony algorithm can effectively shorten the length of search path and reduce time of path search, and has strong decision-making ability and good convergence performance.