The urban heat island effect is one of the primary manifestations of the impact of human activities on the atmospheric system. In this paper, the Space and Time Multiscale Analysis System (STMAS) is used to fuse multi-source high spatial and temporal resolution observations from automatic ground stations, radars, satellites and other sources, and establish a three-dimensional data set of urban heat island. Moreover, on this basis, the characteristics of the intensity change of Beijing urban heat island are statistically analyzed, and a case of an ultrastrong urban heat island (June 11-12, 2021) is selected to analyze its three-dimensional fine structure characteristics in detail. The results show that: (1) In the case of the heat island, the suburban near-surfaces cooled rapidly at night, forming an inversion layer, while the temperature of the urban near-surface decreased slowly, which made the temperature difference between suburban and urban near-surface increased continuously. (2) The warm core structure of the three-dimensional temperature field of this ultrastrong urban heat island was clearly visible in the isobaric surface on the ground and near ground isobaric surfaces below 990 hPa. The wind field anomaly showed the characteristics of cyclonic circulation. It converged from suburb to urban area at low height, causing upward movement that could reach middle and high heights, indicating that the urban heat island effect could enhance the vertical circulation.