According to the hourly meteorological data and hourly air pollutant data in Anshan City, Liaoning Province in 2019, a response relationship model was established based on the generalized additive model (GAM) considering confounding factors such as the background value of urban air pollution and months. The concept of relative risk (RR) was introduced to calculate the quantitative relationship. The influence of three meteorological factors (wind speed,temperature, relative humidity) on PM2.5 and SO2 was analyzed. The results show that all the meteorological factors have threshold effects on PM2.5. The influence percentage of wind speed is the highest. When the wind speed changes below 4 m/s, the relative change of PM2.5 concentration per unit increment is -7.63%. The concentration of PM2.5 changes in a U-shape with the increase of temperature. The threshold of temperature is 10 ℃, and the relative changes of PM2.5 concentration caused by the temperature are -0.56% below 10 ℃ and 0.6% higher than 10 ℃. When the relative humidity is between 18% and 85%, the increase of relative humidity often leads to the increase of urban PM2.5 concentration. When the response variable is SO2, the relative changes of SO2 concentration corresponding to per unit reduction of wind speed, temperature andrelative humidity are -0.91%, -0.43% and 0.98%, respectively.