Constitutional research on euthanasia aims at providing the state’s position on euthanasia. From the point of constitutional right， the dispute centralizes on the essence of ｔｈｅ right of life. The right of life is freedom in essence， so individual can arrange life and death in self-determination， and empower Dr to assistant him to euthanasia. It also can decide un-freewill euthanasia by human dignity， because human dignity prefer to the right of life. But the right of choice should be given family numbers of ｔｈｅ patient.