A method for irradiation based on a fluence map includes determining a shield type of each of a plurality of rows of a fluence map. The method also includes determining, for each of the plurality of rows, a movement curve indicating a relationship between an irradiation dose in the each of the plurality of rows and a moving position of a leaf pair corresponding to the each of the plurality of rows. The method further includes determining an initial irradiation dose for each of the movement curves and synchronizing one of the movement curves based on the shield types of the plurality of rows. The method also includes selecting at least one irradiation dose of at least one point on an irradiation dose axis and generating a control point according to the selected irradiation dose.