This study is to understand and to describe the power that a nurse experiences on nursing practice and then. to present a basic data for nurse's power-development, power improving and empowering. Ethnography was used to understand and to describe experience on exercising various powers occurred on nursing practice. and to analyze and to understand the meaning of a nurse's power. The objects was nurses. Ten nurses who have more than three year's experience were selected as objects from Cuniversity's hospital in Seoul from May of 1996 to August of 1997 through in-depth interview. participant observation, and phone interview. Instruments werw a portable recorder and field notes. I described a case appeared in a data using Agar's 'Pencil and scissors' method right after collecting materials. Then, Idescribed a theme discovered commonly. Followings are the results of the study. 1. There were three categories of relationships with main objects when nurses exercised their power on their practices: a therapeutic caring relationship with patients, a relationship of companion, vertical cooperation, and a constituent person with a doctor, and a relationship of cooperation, and a constituent person with administrative workers and medical technicians. 2. There were many types of nurse's power, tactics and various patient's responses about them. 1) Types of nurse's power to patients were giving information, controling environment, helping for cure, emotional support, and performing discretion. 2) Nurse's tatics for performing power were positive tactics neutral tactics, and negative tactics. 3) Patient's responses were appeared as compliance and noncompliance. Compliance were agreeing. taking nurse's advice, trusting, understanding, being admitted, exposuring himself, and appreciating. 3. There were types of nurse's power and performing tactics. 1) Types of power to a doctor were advice, informing, demanding and mediation. 2) Performings of tactics to a doctor were positive tactics, neutral tactics, and negative tactics. 3) Doctor's responses were appeared as accepting and unaccepting. Acceptings were taking in and appreciating, and unacceptings were denying nurse's advice and authoritative. 4. There were types of nurse's power and tactics about administrative workers and medical technicians and responses about them. 1) Types of power about administrative workers and medical technicians were suggestions and demands. 2) Power performings tactics were positive tactics.neutral tactics, and negative tactics. 3) Responses of administrative workers and medical technicians about nurse's power performing were appeared appeared as accepting and unacce pting. Acceptings were taking in, and unacceptings were denying. Therefore, it can be said that types of nurse's power and performing tactics on nursing practice and nurse's power based on responses of a patient, a doctor, an administrative worker, and a medical technicians are power or influence for agreeing, taking advice, trusting, understanding, exposuring himself, appreciating, and taking in to objects. The results of this study helped to understand nurse's power. I expect that this study will improve nure's power by using expert power, referent power, and legitimate power effectively among powers acmpanied with the origin and that nurses make ef-ort to improve professional knowledge and human nature so that they use this study as a chance to develope expert nursing practice.