Controlling the large-scale haze in Beijing-Tianjin-Hebei region has become a social issue of great attention to government departments and the public. This paper establishes the NO2 diffusion model based on the Gauss plume model, by selecting Shijiazhuang city of Hebei Province as a case which is influenced seriously by NO2 pollution, and analyses the diffusion law, diffusion range and concentration change of NO2. Firstly, the conditions and parameters of the Gauss plume model are introduced, and the related factors affecting the NO2 diffusion are analyzed. Secondly, the pollution sources are classified into point pollution sources (chimneys) and line pollution sources (automobile exhaust), and combines the yearly weather conditions of Shijiazhuang such as wind speed, wind direction, atmosphere stability etc. Then, simulating the diffusion area and concentration change using Stata 13.1 software platform, we found: (1) The formation of NO2 pollution in Hebei Province is affected by special topography and unfavorable meteorological conditions; (2) The atmospheric stability is basically higher in autumn and winter; (3) Industrial emissions are the main source of NO2 in Hebei Province; (4) The concentration of NO2 pollutants near the emission source is the highest, and the concentration gradually decreases with increasing distance. The conclusion of the study has certain practical significance for the design and implementation of government environmental regulation and effective control and reduction of environmental pollution. The conclusion of the study has certain practical significance for the design and implementation of government environmental regulation and effective control and reduction of environmental pollution.