Recently,since stable nitrogen composition (delta~(15)N) in plants records abundant climate and environment information (such as information on temperature,humidity,precipitation and environment isotopes composition),it has been widely used in paleoclimate studies and becomes a powerful tool for understanding paleoenvironment reconstruction and modern climate change. However,some potential uncertainties have always involved in the reconstruction of paleoclimate and paleoenvironment. Among them,the most dominant uncertainty is due to our poor understanding of the relationship between nitrogen isotope ratios of plants and climatic factors,particularly the relationships among nitrogen isotope ratios,temperature and precipitation. Based on summarizing plant delta~(15)N fractionation and nitrogen isotope distribution of different N sources,the effects of environmental factors,e. g.,temperature, precipitation,atmospheric CO_2 concentration,and altitude on terrestrial plant delta~(15) N and their mechanism were analyzed in this paper. Furthermore,the existing and disputed problems in nitrogen isotope study were discussed, and the future trends of nitrogen isotope technique in global change research were prospected. It is pointed out that the technology of nitrogen isotope in plants could not only be used to rebuild paleoclimate (such as reconstructing the sequences of atmospheric CO_2 concentration changes),revealing the trends of climate changes,but also in a certain time and space to reflect comprehensively the characteristics of nitrogen cycling in ecosystem. This will make more readers have a more profound understanding of the field and eventually broaden the development of the field.