Clouds represent weather. Being a modulator of solar heating and thermal cooling of the Earth, clouds are also called "the shutters of the Earth". In 1960, the first meteorological satellite was launched, demonstrating the new era of cloud observation. The acquisition of meteorological satellite cloud images deepens the understanding of the weather and climate change and accelerates the development of atmospheric sciences. In this paper, the principles and methods of cloud detection, cloud phase determination and retrieval of cloud optical thickness and effective radius using satellite data are first summarized. Then, the cloud features of synoptic scale and mesoscale weather processes are emphatically introduced. Finally, two international satellite cloud climatology projects, as well as the perspectives of future cloud observation technology, are presented.