By analyzing the characteristics of the organic matter dliC in different-altitude and high-elevation (Qinghai-Xizang Plateau) lake sediments in China, the informations of climate deduced from the organic matter δ¹³C of the lake sediments are discussed.The results show that the organic matter δ¹³C content of lake sediments is to a certain degree correlative with climatic changes.In general, during colder climatic episodes, the δ¹³C values were lower, and higher during colder climatic episodes in the plateau region.Therefore, the variations of δ¹³C in lake sediments in plateau and plain areas have different climatic meanings.Further study shows that all of the aforementioned results have a close relation with the distributions of C₃ and plants. On the basis of the above-mentioned results, three types of climate of organic matter SUC are divided tentatively,i.e.: (1) in middle-low elevation and altitude areas, the higher value of δ¹³C in lake sediments responds to warmer climate period for C₄ plant effect: (2) in high elevation or altitude areas, where C₄ plant almost disappears, the higher value of δ¹³C in lake sediments responds to colder period; (3) in addition, the climatic indication of δ¹³C in some areas is insensitive because of the influences of such factors as the hydrology of the lake basing the change of sedimeatal environment, the reservation of lake sediments, etc.