Abstract: The attribute of deep groundwater and the hydraulic connection (leakage) between deep and shallow groundwater have always been a topic of research and debate among hydrogeological workers. When collecting and testing hydrogen and oxygen isotopic samples from deep and shallow groundwater in four eastern counties of Handan-Xingtai region, high tritium isotope content was discovered in the groundwater there (15~30 TU, the maximum being 51.1 TU). In this paper, the possibility of shallow groundwater leaking into deep groundwater under specific hydrogeological conditions is examined in the light of the tritium isotopic attenuation in the regional atmospheric precipitation together with the level and quality dynamics of the groundwater, the lithology of aquifers and aquicludes in this area. It is concluded that there is possibility of shallow groundwater leaking into deep groundwater in this area, of which the presence of high tritium content in the deep groundwater there is important evidence.