Abstract: Based on the hourly observation data of "dry" aerosol scattering coefficient and absorption coefficient, as well as the simultaneous monitoring data including visibility (V), relative humidity (RH), and nitrogen dioxide (NO₂) during October to December 2017 in Chengdu, aerosol scattering hygroscopic growth factor (f) was calculated by optical synthesis method, and then the complex response-relationship of f to synergistic action between RH and aerosol components was further investigated. Firstly, there were strong multicollinearity among different indicators including RH, ρ_BC, ρ_BC/ρ_PM1, ρ_BC/ρ_PM2.5, ρ_BC/ρ_PM10, ρ_PM1/ρ_PM2.5, ρ_PM1/ρ_PM10, and ρ_PM2.5/ρ_PM10 by using the method of correlation analysis combined with variance inflation factor (ρ_BC, ρ_PM1, ρ_PM2.5 and ρ_PM10 represent mass concentrations of BC, PM₁, PM_2.5, and PM₁₀, respectively). Subsequently, the explanatory variable set of f which included RH, ρ_BC, ρ_BC/PM_2.5, ρ_PM1/ρ_PM2.5, and ρ_PM2.5/ρ_PM10 were obtained. Secondly, the diagnostic results of f single-variable by adopting generalized additive model (GAM) validated that although RH was the decisive influencing factor of f, f also had significant nonlinear relationship with other explanatory variables (all passed the significance test of α=0.01), especially ρ_BC. Finally, the model of the multivariable influence factors of f were constructed based on GAM and the corresponding independent variables including RH, ρ_BC, ρ_BC/ρ_PM2.5, ρ_PM1/ρ_PM2.5 and ρ_PM2.5/ρ_PM10, respectively. The corresponding adjustment determination coefficient (R²) and the determination coefficient of reduced major axis regression were 0.787 and 0.797, respectively, which significantly improved the simulation effect of aerosol scattering hygroscopic growth factor.