Abstract: In the field of laser welding, welding trajectory was acquired by teaching traditionally. However, teaching has many disadvantages such as low efficiency and complex trajectory generating. By building modules of typical graphics, and a new improved ant colony optimization algorithm was proposed which adopt a new method to update pheromone so that rate of convergence can be increased and local convergence can be avoid , in that case, shortest paths will be find in a short time. What's more, this algorithm has applied in laser welding platform.