On the basis of sources, definitions and relevant concepts of NIS, this paper attempts to review current researches in different type of NIS comparison, performance model comparison, vertical comparison of different innovation systems and NIS researches in underdeveloped countries. Experiences in our country indicate that we need to establish our own NIS from two dimensions: to further define the responsibilities and functions of the government, enterprises, colleges and research institutions and combine them into a complementary system; and to realize vertical integration among different level innovation systems.