Abstract: The setting of anthropogenic heat is a difficult point in the numerical simulation of Beijing's urban meteorological environment. Anthropogenic heat includes sensible heat and latent heat. Anthropogenic latent heat can be obtained by calculating anthropogenic water vapor emissions. This paper uses aircraft observation data to quantitatively estimate the anthropogenic water vapor emissions in Beijing in winter. Results reveal a higher water vapor mole fraction in the downwind direction of the Beijing urban area than in the surrounding area. When an excess signal of urban water vapor was observed, the estimated value of water vapor emission rate was between 58 and 9539 kg/s, accounting for 0.64% to 13.12% of the total water vapor advection in the urban atmospheric boundary layer (background + urban excess). The most important source of excessive urban water vapor emission is the emission of urban anthropogenic latent heat such as natural gas combustion, water-cooled air conditioning system and urban transportation. The difference in the snow melting rate and evaporation rate in the central city and surrounding areas may also have a certain contribution, but the proportion is small.