Abstract: Putting forward a new ant colony algorithm in the continuous space optimization problems－real coding, coupling ant colony algorithm for optimizing continuous variables and real coding based on accelerating genetic algorithm, and dividing solution domain into some subspaces with ACA, solutions are dispersed widely and the optimal solution for the principle of pheromone positive feedback can be find easily. Using the advantages of the two algorithms, through optimizing irrigation regime of rice in Chahayang irrigation district in 2006, the results show that the new method is convenient and accurate, the model can provide scientific basis for making a reasonable irrigation schedule and improving water efficiency, and may give optimization field a new thought.