Reliable data form a basis of precise and quantitative description of geological bodies and processes?Data of isotope geology(including isotope geochronology and isotope geochemistry)are Very Precious for geosclentific researches．The quality of these data is critical in building a reliable database for the study of isotope geology? Therefore，a discussion is given on the estimation and assurance of data of isotope geology in this paper Five aspects are discussed on this topic：a)Importance of clear description of samples and their geological backgrounds；b)Types of methods and instruments used in analyses；c)conditions of using reference materi-als：d)Estimation on the precision and accuracy of analyses and e)equation and parameters used in the calcula-tion．Besides，some analytical methods and reference materials are listed in the pape。