Cancer is one of the main diseases that threaten the health of human.In order to increase the cure rate of cancer,the accurate therapy of cancer must be developed speedily.The most effective method for curing cancer is intensity modulated radiation therapy(IMRT),which can increase the local control rate of cancer and decrease complications of tissues.IMRT is considered to be an important breakthrough in cancer therapy.The dose produced by it is better than 3D-CRT and can achieves better results of therapy,which has been confirmed in the clinical therapies of head cancer,neck cancer,prostate cancer,breast cancer,cervical cancer and pancreas cancer etc.The developing course of IMRT,the methods of intensity modulation,the enforcement process of IMRT and the feasibility test of therapy plans are emphatically introduced.