As one of the products of social division of labor， the medical industry must involve the exchange due to the division of labor， so the doctor?patient relationship has a contractual side. From the perspective of medical history， the modern doctor?patient relationship satisfied the subject elements， the object 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 attribution of the doctor?patient relationship. There seems to be conflicts between emphasis on 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”. 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， and contractuality is the form. The Form is deviate from the essence should be vigilanced. But if the form is ignored or the side effects are exaggerated， it will be difficult to achieve the essence.