Law of Science & Technology has not been recognised as independent legal system as the same level as civil, criminal, administrative and commercial law. It took a certain amount of time before administrative law, commercial law and economic law had been accepted as an independent legal system. Therefore, if there is rational ground, Law of Science & Technology will likely evolve into independent legal system. In this paper, the author reviews the existing discussion about the definition of law of science and technology and considers rational ground of it. It is dynamic process that certain legal system has been accepted as independent legal system. It comes from legal scholar's proactive response to the change of specific social phenomenon. The Administrative Law, Labor Law, Commercial Law, Economic Law recognized as an independent legal system have common point as follows. First, the new environment which the existing legal system (civil law or civil law and criminal law, etc.) does not cover has appeared. Second, the new legal system has special and unique legal system that existing legal system does not have. Law of Science & Technology has these characteristics. First, even though the history of science and technology is very old, positive and negative impact of science and technology on society has exceed certain limitation after the Second World War. In particular, the dangers of science and technology could lead to the degree of extinction of the human race. Therefore, while the need to regulate the science and technology increases, the existing legal system is not designed for this purposes. Second, a new legal system named the law of science and technology have a specific purpose to enhance the quality of human life by steering science and technology, which existing legal systems do not have. Therefore, there are sound ground to believe that the law of science and technology will be considered as independent legal area as the same level as administrative law, labor law, commercial law and economic law.