We employ the improved ant colony algorithm(IACA) to investigate the load distribution optimization problem of hot finishing mills. Firstly, objective functions and constraints of load distribution are established. In order to avoid the stagnation of ant colony system(ACS) in accelerating convergence process, IACA makes improvement on the calculation of state transition rule by updating the local and the global pheromone concentration and introducing constrained ant-visual heuristic function as well the int...