The earliest function of clocks and watches was to keep time. With the development of science and technology, the functions of clocks and watches are gradually diversified. From the achievements of mechanical physics in Galileo era to the development of atomic physics and information technology, the functions of clocks and watches are diversified. From simple timing to becoming an ornament, it has many functions, such as timing, information processing, navigation, monitoring and so on, which embodies the change of clock function under the influence of science and technology.