In this study, aerosol samples were collected in different cities, and morphologies and elemental compositions of individual particles were determined by Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectrometer(FESEM-EDX). Size distribution of individual particles in FESEM images were further analyzed by an image analysis system. The result shows that mineral, soot, and spherical particles(fly ash and secondary particles) were dominant particles. The quantity proportionof mineral particles of Beijing aerosol was the highest, the amount of fly ash and soot of Zhengzhou aerosol was the highest, and the quantity proportionof regular mineral particles of Shenzhen aerosol was the highest in three cities. Number-size distribution of individual aerosol particles was unimodal in three cities. Particle size of Shenzhen aerosol was relatively small, followed by Zhengzhou, Beijing. Sources of individual aerosol particles of three cities were partly influenced by traffic pollution source, but the effect of coal burning on Beijing and Zhengzhou could not be ignored.