Conformal intensity modulated radiotherapy is a precise radiotherapy planning system, which is widely used and more advanced. During radiation therapy, it can ensure the consistency of tumor target area in shape and dose, achieve the maximum high dose of tumor target area and the protection dose of surrounding organs, and reduce the damage of surrounding organs. Through the activity of multi-leaf grating, conformal intensity modulation radiation therapy can adjust the dose in the target area with fluctuations of not more than plus or minus 5%, which can basically achieve the dose uniformity in each target point in the radiotherapy target area.