The millimeter-wave dual-polarization cloud radar has a strong capability to detect small particles, able to detect cloud particles with diameters of a few micrometers to weak precipitation particles. It can penetrate clouds to describe their internal physical structure and continuously monitor changes in the vertical profile of clouds, compensating for the shortcomings of other remote sensing methods. Using the millimeter-wave dual-polarization cloud radar, continuous observations of cloud radiation transmission in the atmosphere can be achieved, obtaining significant parameters including macroscopic cloud thickness, cloud height, cloud amount, and number of cloud layers, as well as microscopic cloud particle size, concentration, drop size distribution, and ice and liquid water content. It is used by meteorological bureaus, airports, ports, and research institutions for cloud and fog detection and short-range precipitation detection.