The rapport of doctor-patient is always the issue for medical society and the public. People care about it because almost all of them suffer from illness off and on in their whole lives. Yet the relationships are changeable from time to time. From the ancient Greek and Rome time, to the tenth century of Christian Age, the decision side was always on the doctor's side. Until the modern time of the last century, the decision model has slowly changed into the hands of both sides. From the perspective of medical history, we learned doctors did not converse much. They were asked to behave themselves, but they were not demanded to explain situations of patients or their decision rationales. But time has changed, through the advances of medical technology; there were overwhelming emerging medical procedures and surgery. Simultananeouly, the concurrent medical legal suits have occurred. The Court Judges had to consider not to violate professionalization of medical physicians, the fact of caring custody, and also to protect patients from being abused of newlydeveloped medical procedures or surgeries. Judges were trying to give patients freedom of autonomy in limited situations. That was a dilemma for Judges at that time. But Judges still tried their best to innovate the ”informed consent” for protection of patients from novel procedures or from dangers, and also pushed to communication from doctors to patients at the same time. This article is about these two aspects: the birth of informed consent and co-decision making of doctors and patients.