Abstract: Based on the impact of the urban underlying surface on the transmission and diffusion of air pollutants, two blocks with different development years and spatial morphological characteristics in a residential area in Beijing were selected as the research objects. Using the research method that combined atmospheric environmental quality monitoring and computational fluid dynamics wind environment simulation, the ternary relationship and action mechanism of "urban form-wind environment-air pollution" on the urban block scale were analyzed. The scientific basis for rationally planning the spatial form of urban blocks, building a green and healthy city, and forging a harmonious and livable community was provided. The results of the study show that wind speed is one of the main factors affecting the mass concentration of air pollutants in the block. Improving the internal ventilation conditions in the block is beneficial to the migration and diffusion of air pollutants. The internal wind environment of the two blocks with different spatial morphological characteristics also showed obvious differences. The internal air exchange capacity of the block with dense buildings and relatively closed space was weak, and it was not easy to transmit and diffuse air pollutants. Five urban morphological parameters, namely, building density, enclosure degree, building average volume, building average height, and building height standard deviation, reflecting the spatial morphological characteristics of the block, are significantly related to the internal wind speed of the block. Among them, the building density, enclosure degree and wind speed are negatively correlated. Increasing the height difference between adjacent buildings is conducive to the vertical migration of pollutants and the high-altitude dissipation. Therefore, in urban block planning on the micro-scale, the effects of plane layout, vertical design, and building selection on block ventilation conditions and the dissipation of air pollutants should be comprehensively considered to improve the ambient air quality of residential blocks.