Groundwater resources in the Northern Henan Plain were studied using isotope analyses to improve assessment accuracy. By analyzing elements and isotope changes in groundwater, researchers identified recharge sources and calculated the amount of water replenished by the local river and the Yellow River. This helped enhance the precision of groundwater resource assessment. Additionally, estimating the renewal velocity of shallow groundwater using isotope techniques is crucial for sustainable groundwater use. The study found that these methods can indirectly improve the accuracy of groundwater resource assessment in the region.