Abstract: Ten years' pollution risk of a petrochemical contaminated site on its downstream groundwater source in a provincial capital city of northwest China was predicted on the basis of groundwater flow and solute coupling model and by using GMS software. Several realistic groundwater pumping scenarios were used, but the natural degradation of petroleum hydrocarbon was not considered. Thus all the predicted risks were exaggerated to some extent. According to the modeling results, the petrochemical hydrocarbon pollution plume can not be transported across the border of the groundwater source. This is due to the special hydrogeological structure of the study area. Only thin layers of Quaternary aquifer are distributed in the petrochemically contaminated site, while the groundwater source is in the rifted-basin downstream area. Under this condition, the recharge of groundwater from the petrochemically contaminated site to the groundwater source is very limited, and the main recharge to the groundwater source is from the Yellow River. The drag of the contamination plume by groundwater pumping in the groundwater field is very weak. Taking long-term interest into consideration, the authors hold that an old Yellow River channel called ‘south channel’ should be restored to stop the intrusion of the pollution plume, because water in this channel flows between the petrochemically contaminated site and the groundwater source, and hence the channel can create a hydraulic barrier blocking the intrusion of the pollution plume and at the same time enhance the recharge to the groundwater field.