Abstract: In order to get a time series that represent the total characteristics of some regions, objective analysis and regional-averaged method are widely used to handle observation data. Barnes objective analysis method is a convergent weighted-averaging interpolation scheme which is most generally used in meteorological and ocean field. The characteristics of the elements such as soil temperature, air temperature (include max and min temperature), air pressure etc. On the Tibetan-Qinghai Plateau were analyzed by using these two methods. It is found that when data are not good in continuity, the influence caused by the different region of observe station must be removed in order to get a reliable conclusion, otherwise an erroneous conclusion is got, so this question should be paid attention to.