To study the differences in scattering characteristics caused by differences in aerosol hygroscopicity, hygroscopic growth models for two types of aerosol are built according to thermodynamic principles and Brunauer-Emmett-Teller theory, respectively. Based on these models, the scattering properties of aerosols at relative humidities from 40% to 90% are calculated using the discrete dipole approximation method. It is shown that when hydrophilic particles, e.g., four typical inorganic salts, reach the deliquescent relative humidity, their size increasese xponentially, whereas that of hydrophobic particles (e.g., soot) increases slowly and nonlinearly with an increase in the relative humidity. Results are consistent with experimental measurements. Using established hygroscopic growth models and the measured refractive index-humidity growth law, the relationship between relative humidity, and aerosol particle growth factor is calculated and analyzed for the particle size range of 0.1--1.0 μm. It is found that the scattering growth factors grow exponentially after deliquescence, their values increases by tens of times at 90% relative humidity, and scattering factor growth curve of sodium chloride inorganic salt agrees well with experimental results. However, the maximum scattering growth factor of hydrophobic particles is only 1.07 at the same humidity, which is much smaller than that of hydrophilic particles. These results provide theoretical support for the assessment of the climatic effects of aerosols and for accurate measurement of aerosol concentrations and atmospheric visibility.