Cryosphere meltwater has been recognized as an important source of local water resources.However,there are a few assessments on the contribution from permafrost active layers groundwater.In this study,taking Shiyang River basin as an example,we quantifies the fraction from permafrost active layers groundwater and glacier snow meltwater to runoff in the basin,an in-land river basin of Northwestern China,where glaciers were disappearing and permafrost was in degradation.A total of 343 event-based precipitations samples at six stations of Xidahe,Jiutiaoling,Anyuan,Wuwei,Yongchang and Minqin in Shiyang River basin,129 river water samples from Dajing River,Gulang River,Huangyang River,Jinta River,Xiying River,Dongda River and Xida River,10 spring samples at mountainous region,11 reservoir water samples,36 permafrost active layers groundwater samples and 22 glacier snow meltwater samples have been collected and analyzed for their isotopic compositions.Results indicated that the runoff is a mixture of precipitation,permafrost active layers groundwater and glaciers snow meltwater in the basin,and there is a frequent exchange between river water and spring water in mountainous region.The shallow groundwater recharging height is at the altitude of 3700m,whereas the deep groundwater is principally maintained by palaeowater with some modern recharge in the basin.Glacier snow meltwater only accounted for 3% of outlet river water in Shiyang River basin,and this contribution is 7%,5% and 1% for three tributaries:Dongda,Xiying and Jinta rivers,respectively.However,with respect to the permafrost active layers groundwater,this contribution rate is 23% for Shiyang River basin,and is 28%,22% ,13% ,16%,9%,24% and 27% for Dongda River,Xiying River,Jinta River,Xida River,Huangyang River,Gulang River and Dajing River,respectively.As the main runoff area,the contribution from water in glacier and permafrost belt has accounted for 82% of the outlet river water.The results confirmed that permafrost active layers groundwater has played an important role in runoff of in-land river basins,and it is of great significance to evaluate its influence on hydrological process under climate warming scenario.