Todays medical image guided radiotherapy(IGRT)has become a mainstream radiotherapy technology.It mainly makes an integration of medical X-ray image equipments,such as CT or cone beam CT(CBCT)or KV level digital X-ray machine(DR),and medical high energy accelerator apparatus,and form a kind of advanced radiotherapy mode based on real-time X-ray image guidance.However it has some problem that patient subjects to a certain amount of additional X-ray radiation dose damage,due to repeated X-ray imaging location and verification.This also caused the doctors some concern and worry with green treatment initiative in clinical practice.In addition,if there are conditions,further image observation of patient prognosis and review,also need a doctor to make multimodal imaging evaluation by the combination or integration of high field strength magnetic resonance imaging(MRI)and functional magnetic resonance imaging(fMRI).3.0T high field strength magnetic resonance imaging machine has become a mainstream trend of current green imaging device.It has higher tumor tissue imaging resolution and more analysis functions of DWI,DTI and related prognosis evaluation,and its peripheral image distortion rate is becoming more and more small.Therefore,the concept and technique of green diagnosis and treatment based on the integration of 3.0T magnetic resonance imaging guided radiotherapy system arises at the historic moment.This paper briefly introduces the main progress of integrated high field magnetic resonance imaging(MRI)guided radiotherapy system and presents several important technical problems,including new problems and new processing methods in the new radiation treatment planning and dose calculation.