Based on discrete phase model(DPM), a simulation was carried out to study the aerosols with diameter of 10 microns dispersed in different kinds of geometrical street canyons when referenced wind velocity Zref=2m/s. In the simulation, renormalization group two equations model was used as turbulence model. The numerical results indicated that due to urban wind field the air in the street canyon present vortex’s flow, street canyon aspect dimension ratio have crucial effect on the aerosol concentration distributing. Moreover the nondimensional concentration of the street canyon with the aspect ration of B/H=0.5 and H1/H2=2 is more dense than others.