Abstract: Complex network theory is a rising important branch of the complexity science, which provides a new scientific method for systemic structure analysis by depicting and describing through the statistical parameters of the systemic network structure. Through the analysis of the statistical parameters of the complex network, scientists have discovered that the complex world may present two phenomena: the small world and scale-free. Through both the tools of small world and scale-free, we may find in the world of complex networks the simple laws of science, which will provide us with a powerful scientific tool to analyze the complicated worlds of science. Complex network theory is becoming a new world view and way of thinking, providing a new scientific method and opening a new window for us to recognize the complex world.

Key words: complex networks; complexity science; perceive the world; small world; scale-free