[Objective] This study was conducted to provide a scientific theoretical ba- sis for pollution forewarning and agricultural planning. [Method] 15 PAHs were stud- ied for pollution characteristics, source analysis and ecological risk assessment at 60 sites in Hohhot farmland. [Result] The results showed that the total contents of 15 PAHs （：EPAHs） in 60 sampling points of Hohhot farmland were in the range of 114-948 ~g/kg, with an average content of 338 pg/kg. According to soil PAH as- sessment standards, more than 70% of soil in Hohhot City was lightly polluted, and there were no heavily-polluted points. The soil of the area was mainly polluted by PAHs with high molecular weights, which accounted for 74% of the total content. The soil in suburban farmland of Hohhot suffered from the heaviest pollution. Quan- titative analysis showed that PAH pollution in Hohhot farmland was mainly from combustion of coal, coke and timber and automotive exhaust emission. [Conclusion] Ecological effect interval method and method of equivalents equivalent to benzo （a） pyrene toxicity benzo [a] pyrene both proved that there is certain potential ecological risk for soil of Hohhot farmland, and PAHs with high molecular weights such as benzo （a） pyrene and dibenzo [a, h] anthracene are main potential pollutants with ecological risk.
