As one of the products of social division of labor, the medical industry must involve the exchange brought about by the division of labor, so that the doctor-patient relationship has a contractual side. From the perspective of medical history, the modern doctor-patient relationship satisfies the main elements, the essential elements, the essential elements and the formal elements of the contract. However, regardless of the responsibility of the medical party or the welfare of the people in the country or society, public welfare should be the essential attribute of the doctor-patient relationship. Emphasizing the contractuality of the exchange of equivalence, and the emphasis on the public welfare of the patient"s "get" should be greater than the "pay", there seems to be conflicts, and it is necessary to be alert to the risk of the contractual nature of the doctor-patient relationship. Contractuality is the manifestation of modern doctor-patient relationship, and medical public welfare needs to be realized in this form. Public welfare is the essence, contractuality is the form, and vigilance is to deviate from the essence. But if you ignore the form or exaggerate the side effects, it will be difficult to achieve the essence.