Recent developments of information technologies are leading the advent of the era of ubiquitous healthcare service, which means healthcare services at any time and at any places. In a home, the ubiquitous healthcare service requires some context aware system for smart services using home network. In this paper, we propose a systematic design tool of a context aware system for ubiquitous healthcare service in a smart home, which is composed of a home gateway, a home server, a PDA, home network healthcare devices, and wearable sensors. We developed a context aware framework to send information from wearable sensors or healthcare devices to healthcare service entities as a middleware to solve the interoperability problem among sensor makers and healthcare service providers. And, we propose a design tool of ubiquitous healthcare services with the context aware framework in a systematic way. In order to show the feasibility of the proposed system, an application example is given, which is applied to a self check service.