Thirteen polycyclic aromatic hydrocarbons (PAHs) in 32 urban dust samples collected from the main roads of Guiyang City, Southwest China were measured using GCMS method, and their health risks were assessed using the methods proposed by US Department of Energy and US EPA. The results showed that PAHs in urban dusts were in the range of 1291-9215 μg·kg^-1 (mean: 4006 μg·kg^-1), which was modest at the global scale. These PAHs were mostly originated from vehicle emission and domestic coal combustion based on the principal component analysis. Health risk assessment suggested that the noncarcinogenic hazard and the cancer risks were mainly stemmed from the respiratory activities. The integrated noncarcinogenic hazard index was much less than one, while the integrated cancer risk was at least one magnitude higher than that of the acceptable cancer risk, indicating certain cancer risk cannot be avoided. Among the thirteen PAHs, BaP and DBA contribute the most to the integrated cancer risk, which deserve more concerns.