Abstract: The development of science has enabled people to truly understand the objective world. In previous studies，researchers from the perspective of scientific philosophy tried to answer“what is science”，interpret the nature of science，and clarify the basic features of science. In a particular society，science is a reliable system for human beings to learn about the objective world，a process in which they gain experiences and form conclusions through reliable thinking，attitude，means and methods. Science comes from philosophy but it is not philosophy itself；at the levels of ontology，epistemology，and methodology，the two are inseparable but are very different. Views on the essence of science evolve along with the development of science. Based on these research findings and the contemporary points of view，clarifying the literal meaning of science，restudying the history of science and the evolutional process of views on the nature of science，and learning about the characteristics of science from real life will help to more fully understand science and grasp its connotation.

Key words: science, nature of science, history of science, scientific facts, scientific connotation