Most researches, of communication field in Taiwan, focus on mass communication. In comparison, less attention is paid to the dimension of interpersonal communication. However, interpersonal communication is the basis of human life. It’s quite important in connection with the exploration of this aspect. In the field of interpersonal communication, doctor-patient interaction plays a unique role. When a doctor and a patient interact, two parties with different action logic coordinate and converse constantly. What this research is about to explore is the appearance of action logic between a doctor and a patient. This research uses Oevermann’s Objective Hermeneutics as the research method, and introduces the way of case study to explore the general action logic within doctor-patient interaction. This research interviews a female doctor of Family Medicine Department and a female patient who takes medical treatment due to a stomach ulcer. In the analysis consequence, we can find out that both sides’ action logic encounter in the topic of trust. Trust affects the strategy of action between a doctor and a patient. In trust logic of two parties, the common trust of a patient and a doctor is just the scientific system of western medicine. What two parties trust less are the medicine system and the individual in the system. Besides, we even discover that market logic and bureaucracy place many restrictions on establishing the great relationship between a doctor and a patient. Therefore, we must take serious on the problem of the structure, and then we are able to find a workable solution to the problem of the present doctor-patient communication.