Electrochromic materials show reversible color-changeable characteristics, which are widely used in smart windows, displays, adjustable reflective mirrors, electronic paper, military camouflage and other fields. Compared with other kinds of display devices, electrochromic display devices have advantages of multi-colors, high contrast, no blind visual angles, and maintainable color after power off. As a typical cathodic colored electrochromic material, molybdenum oxide exhibits advantages of short response time and colored state closer to the sensitive wavelength band of the human eye to light, so that the electrochromic devices composed of molybdenum oxide is important in the research. This paper briefly introduces the definitions and applications of electrochromism, electrochromic materials and devices. In particular, electrochromic technology recently realized a demonstration application in smart phones, indicating the good prospects for the future development of electrochromic technology. We summarized mainly the research progress of the preparation of molybdenum oxide films, the modification of molybdenum oxide, and the molybdenum oxide based electrochromic devices. Finally, we presented current existing problems and solutions on molybdenum oxide based electrochromic films and devices with development prospects.