Aerosol nanoparticle generation is a key step in calibrating aerosol instruments, examining nanoparticle properties, and investigating aerosol formation mechanism in photochemical smog systems. An aerosol nanoparticle generation system (including an atomizer and a diffusion dryer) was developed and evaluated in this study. Aqueous solution of NaCl and isopropanol solution of DOS are used to generate solid and liquid aerosols, and the size distribution is measured by a scanning mobility particle spectrometer (SMPS). With the concentration of 0.01-0.50 g x L(-1) and the carrying gas flow rate of 1.64-3.67 L x min(-1), generated aerosols have the geometric mean diameter of 25-51 nm and the total number concentration of 10(6)-10(7) cm(-3). The stability of the generation system was demonstrated. During the three-hours consecutive operation, the variations of the geometric mean diameter and the total number concentration are less than 6% and 12%, respectively.