For nursing as a science to establish a unique system of knowledge, nursing researches should include philosophical activities such as critique, analysis and synthesis. As a consequence of these activities, nursing science comes to add up more abundant content of knowledge and have a more refined scientific system. In short, nursing science can be developed in respects of tools and methods through philosophical researches, i.e., philosophy of nursing science. Traditionally, the task of supplying individual science with pertaining methodological principles has been due to philosophy, or philosophy of each Scientic discipline. Philosophy of nursing science establishes a dem arcation between nursing and non-or pseudo-nursing, so that the unique natne of nursing can be revealed. Systematizing the particular knowledges or informations discovered through empirical resear ches, philosophy of nursing science, as a part of rational activities to construct its scientific theories. Owing to philosophy of nursing science, conce ptual frameworks or theories settled in various branches of nursing science can be integrated into a holistic system. Philosophy of nursing science can include argu merits on standards, values, goals and intents of nursing behavior, so that their interrelational networks can be understood. Philosophical discussions can offer nursing sci ence positive ways to more extensive development, preventing it from indulging in particular or exclusive inclination. And philosophy of nursing science in itself should also keep a liberal attitude to overcome preconceptions concerning methodology of nursing science.