Five soil profiles were selected in typical epikarst spring catchments in Nanchuan District, Chongqing Municipality as objects of the study on rules and controlling factors of the vertical migration of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in the soils. Soil samples were collected from every soil layers, 10 cm thick each, of the soil profiles for quantitative analysis of the PAHs with gas chromatography-mass spectrometry (GC-MS). Results show that all the 16 PAHs were detected in all the 5 soil profiles, varying in the range of 161~3 285 ng g^-1, and averaging 987 ng g^-1 in concentration. In the soil profile at the Hougou epikarst catchment, high-ring PAHs were in dominancy, while in the soil profile at the paddy field of the Lanhuagou spring catchment and at the Shuifang spring catchment, low-ring PAHs were. However, in the soil profiles in pine forests at the Baishuwan and Lanhuagou spring catchments, high-ring PAHs dominated the 0~2 cm soil layers, but low-ring PAHs did the soil layers below 2 cm. From the contents of PAHs and changes in composition along the profiles, it could be inferred that low-ring PAHs migrate easily. But in soil profiles with a thin surface soil layer, artificial disturbance, like plowing, make it easy for high-ring PAHs to migrate. Among the five soil profiles, only the one in the Shuifang spring catchment witnesses the highest mobility of PAHs. As in karst areas, the surface soil layers are generally thin, PAHs migrate easily, thus polluting epikarst spring water. Multiple regression analysis between the total PAHs and physicochemical properties of the soils shows that total organic carbon (TOC) is the main factor controlling the migration of PAHs in the Hougou, Lanhuagou and Baishuwan spring catchments, while in the Shuifang spring catchment, there is no main factor impacting migration of PAHs.