Abstract:The estimation of groundwater recharge resources is an important basis for sustainable development and utilization of groundwater resources. Traditional groundwater resources evaluation work often uses water balance method or Darcy's law to evaluate groundwater recharge resources, and rarely uses environmental tracer methods. Environmental tracers have important value in groundwater recharge research, especially in arid and semi-arid areas, which is a very simple and reliable evaluation method. In this paper, basic principles of two common environmental tracer (3H, Cl) methods have been introduced, they are tritium peak method and chlorine mass balance method, and their main applications in groundwater recharge research have been introduced as well. The chlorine mass balance method can not only estimate the amount of groundwater recharge, but also study the impact of vegetation cover changes on groundwater recharge and trace the groundwater recharge history and climate change.