Organochlorine pesticides (OCPs) in underground river water in Chongqing typical karst area was analyzed by GC-ECD. The results show that the total concentration of OCPs ranges from 3.41 to 51.34ng/L and averages 13.23ng/L;the concentration of DDTs ranges from 0.07 to 2.37ng/L and averages 0.72ng/L;the concentration of HCHs ranges from 1.16 to 39.82ng/L and averages 7.89 ng/L. Wantan underground river is the most seriously polluted river in Nanchuan with the concentration of OCPs reaching 51.34 ng/L, which mainly resulted from the paper mills’ waste water. Comparing with other surface rivers in the world, the concentration of OCPs is in low level in the underground river. Due to the binary structure in karst area, once contaminated, it will have an impact on the underground river. Therefore, the investigation of underground river has important practical significance.