This data set is the the hydrogen and oxygen isotope ratio data of water samples collected in the Ngangla Ringco, Renqingxiubucuo, Mapam Yumco, and Laangcuo during the River and Lake Source Investigation in 2017. It is used to acquire basic physical and chemical indices of lakes. And it can prepare for the following modern observation studies of lakes environment research. The water sample collection time is from August 2017 to September 2017. The sampling sites are Ngangla Ringco, Renqingxiubucuo, Mapam Yumco, and Laangcuo. The data is measured by the Environmental Laboratory of the Institute of Tibetan Plateau Research. The instrument used is the wavelength scanning cavity ring-down spectrometer made by the American Company Picarro. Each sample is measured twice and two data is obtained when measured. The average of the two data for the same indicator for each sample is used when analyzing. Test accuracy: (standard deviation, SD): δO18 ≤ 0.15 ‰, δD ≤ 1.0 ‰.