Abstract: Millimeter cloud radar is one of the powerful instruments for cloud vertical structure observation. It can continuously monitor cloud changes and obtain complete information of cloud vertical structure including the cloud base height, cloud top height, and cloud thickness etc. Meanwhile, radiosonde observations can directly and accurately describe the vertical structure of atmospheric humidity due to its in situ measurement advantages. Observations of radiosonde can be further processed to generate cloud vertical structure information, which can then be used as a data source to validate the cloud vertical structure observed by millimeter cloud radar and assess the performance of millimeter cloud radar for cloud vertical structure observations. In this study, based on the millimeter cloud radar reflectivity data and sounding data collected at Beijing Observatory from 28 October 2014 to 17 February 2015, appropriate methods for calculations of cloud boundary height from the millimeter cloud radar and radiosonde observations are designed or selected, and their consistency is analyzed. The results show that the cloud vertical structures derived from cloud radar and radiosonde observations have a good consistency regarding to the cloud base height, cloud top height in low or middle level, and its vertical stratification. Due to the limitation of the detection capability of the millimeter cloud radar, it can not detect cloud tops above 10 km height. Thereby large differences are found in high-level cloud top height between millimeter cloud radar and radiosonde observations.