Abstract: There is increasing concern regarding the potential health risks associated with inhalation of ultrafine particles. The particle samples of 0.08-2μm were classified as accumulation range. These particles originated from the coagulation of smaller primary particles emitted from combustion sources, condensation of volatile species, gas-to-particle conversion, and finely ground dust particles. The nuclei and accumulation ranges included most of PM_2.5 size fraction (particulate matter with a nominal aerodynamic diameter less than or equal to 2.5μm). Microscopy and size-distribution of mineral particles, soot aggregates, spherical particles and other particles (biomass, salt, fibers) in cafeteria and barbecue restaurant was studied by high resolution field emission scanning electron microscopy (FESEM) and image analysis technologies (IA). The FEEM analysis showed that minerals had regular and irregular shapes. In cafeteria, the mineral particles were dominated by number and volume, accounted for 69.23% and 80.13%, respectively. Minerals particles showed a bimodal number-size distribution, with a greater peak in 0.2-0.3μm range and lesser peak in 0.3-0.4μm range. The particle sizes less than 0.5μm accounted for 58.90% by number. In contrast, volume-size distribution exhibited a single peak in the range of 1-2.5μm, and that in the range of over than 0.5μm accounted for 70.48%. In barbecue restaurants, mineral and other particles were dominated by number for 45.67% and 44.86%, respectively. Mineral particles concentrated in 0.2-0.4μm range by number mainly. And in the range of less then 0.5μm accounted for 39.41%, the mineral particles in 1-2.5μm range had a considerable contribution, and in the range of large then 0.5μm accounted for 52.33% by volume-size distribution.