As a result of economic development, people lives longer than before and healthy lifestyle becomes the most important pursuit of the society. In modern society, the average life span is over 70 and the ratio of aged population is forecast to rise to 20% in 2020. And they will have a chronic illness such as the obesity, high blood pressure. Thus they should have the health screening to prevent disease or emergent health condition of chronic illness so that they can be observed by seamless U-Health Services [1,2,3]. Basically U-Health Service could break the time barrier and a location barrier, and collect and analyze biometric data. And if some symptom would be detected by U-Health System, then U-Health Service would send instant alerts to patients. The symptom would be determined by collected biometric data and predefined conditions of each patient . In this paper, we define U-Health as health management service that can be provided without the restriction of time and location. In other words, for the purpose of improving the quality of medical services for disease prevention, diagnosis, treatment, and follow-up as well as the necessary healthcare services, U-Health Service is able to provide seamless patient's health condition state and alert for symptom. U-Health Service collects personal biometric data, so that the collected information is private and should be ensured security and safety of personal information. In addition, unlike other IT service system, malfunction of U-Health Service directly affect a person's life. However, U-Health Services did not mention and research security of personal information and did not try to connect with external IT services and network. Therefore, a variety of U-Health Services have not been activated. In this paper, OTP (One Time Password) for ensuring the security [5-7] and stability of U-Health Services is proposed. With OTP, proposed U-Health Service securely provides a service-based key management technique, real-time analysis of patient's health state, and alert notification for patients.