Nowadays, intelligent evacuation systems were widely used in large-scale integrated buildings. When emergencies such as fires, how to combine complex building structures and plan a reasonable and safe evacuation route had become one of the key research topics. A multi-start and multi-egress path planning method based on improved A* algorithm is proposed in this paper. The three-dimensional grid method was used to establish the floor map. By increasing the turning penalty value, the number of path turns was reduced. At the same time, the real-time information of the fire affected area was combined with the distance of the fire center point to improve the evaluation function, so that the search direction was more clear and the search efficiency was improved. The searched optimal path calculates the direction of each guide mark in the floor, thereby guiding people at different positions to evacuate from the optimal path. By using Matlab simulation, compared with the traditional A* algorithm, the improved A* algorithm was more smooth and the running time was shorter when calculating multi-start and multi-export evacuation path planning. At the same time, combined with fire information to ensure the safety of evacuation path, the Pathfinder evacuation simulation experiment shows that compared with the traditional static guidance mark, the improved guidance algorithm dynamically adjusts the direction of the guiding sign, so that personnel can safely and quickly evacuate and escape.