Aiming at the recently study which does not take into account the dynamic changes of the traffic capacity, the optimal path of disaster relief vehicles from disaster relief points to earthquake-striking spot is calculated based on improved ant colony algo- rithm. The improved algorithm modifies the transition probability according to the traffic capacity, adopts adaptive pheromone updat- ing strategy. The simulation results show that it can improve convergence rate and capacity of searching optimal solution. The im- proved algorithm can provide important decision-making basis for the post-earthquake rescue, which has important practical signifi- cance.