12-year LIDAR observations of tropospheric aerosol vertical distribution using a Mie scattering LIDAR in Hefei ($31.9^{circ}N$, $117.2^{circ}E$) from 1998 to 2009 are presented and analyzed in this paper. Characters of temporal variation and vertical distribution of tropospheric aerosol over Hefei are summarized from the LIDAR measurements. The impacts of natural source and human activities on the aerosol vertical distribution over Hefei could be seen clearly. Dust particles from the north in spring could affect the aerosol distributions below about 12 km over Hefei, and aerosol scale height in April reaches $2.29{pm}0.68;km$. Both LIDAR measurements and surface visibility imply that aerosols in the lower troposphere have been increasing since about 2005.