The rapid expansion of cities has caused enormous changes in the underlying surface, and coupled with the intensification of human activities, it has resulted in a series of ecological and environmental problems, such as urban heat island, air pollution, and so on. Through combining building height and air pollution source information, and using the computational fluid dynamics (CFD) model, this study simulated the distribution characteristics of wind speed, temperature and SO₂ concentration under the condition of urban three-dimensional expansion, and then the analysis was performed on the influence of three-dimensional expansion on air environment diffusion during winter and spring in the Shenyang Tiexi District under the urban landscape pattern of 2005 and 2011. Monitoring data from 10 sampling sites were used to validate the model. The results showed that the R² values for wind speed, temperature and SO₂ were 0.76, 0.79 and 0.64, respectively. The wind speed, temperature and SO₂ concentration distribution pattern at the same height of the study area is obviously different because of the differences in urban building height, density and layout between 2005 and 2011. From 2005 to 2011, with the change in the urban architecture landscape pattern, the city corridor significantly changed.