Galileo summed up the law, the law of inertia and Galilean relativity principle from the experiment. In order tooverthrow the many assumptions of Aristotle's physics, laid the foundation of classical mechanics, refutedPtolemy's geocentric system, strongly supports the heliocentric theory of Copernicus. He overthrew the systemexperiment and observation is purely speculative the traditional view of nature, created the experimental facts of modern science and rigorous logic system