Abstract: The Zongri Site is located on the north side of the Huanghe River, between two villages Kaligang and Banduo of the Bagou Township, Tongde County, Qinghai Province. Zongri Site was firstly considered as the western most site of the Majiayao Culture. However, with the excavation going on, more and more evidence showed that it might represent a new kind of archaeological remain. Numerous potteries were found with a particular style (Zongri Style) which was completely different from that of the Majiayao, and the unique pronely extended burial of the body which is common in these tombs is rare in both Majiayao and other contemporary cultures. Sites with similar characteristics have been discovered along the the Huanghe River and its branches in the Gonghe Basin. They therefore, together with the Zongri Site were proposed to be a relatively independent culture called the Zongri Culture which is dated to 5200~4100aB.P. according to the tree-ring correction of 14 C dating and periodization by potteries. In the area of the Zongri Site, there are altogether 341 tombs being discovered. Among them 175 have been definitely identified as belonging to the Zongri Culture, while others with their age tentatively undetermined. Those Zongri Culture tombs can be classified into three periods due to the assemblage of the buried potteries. 24 human bone samples were collected from both determined tombs (18) and undetermined tombs (5, among which M32 is a joint burial tomb, with 2 samples collected). The human diet from the Zongri Site was investigated by stable isotopic analysis on these bones. In general, all samples are well-preserved. Their C/N (mol ratio) ranges from 3.16 to 3.23 which is within the standard (2.9~3.6), they are thus believed to be uncontaminated and can be used as palaeodietary indicators. Stable isotopic analysis on these samples(δ13 C: -12.20 ‰ ~-8.49 ‰ and δ15 N: 7.59 ‰ ~9.23 ‰ )shows that C4 plants (mainly millet) was the main food and animal proteins are also detectable. The source of animal proteins may come from hunting, fishing and/or domestic animals. Ample mammal bones and bone tools especially fishhooks unearthed demonstrates that hunting/fishing was one of the livelihoods of the inhabitants. However, it is hard to estimate the contribution of domestic animals due to the lack of data on related work about live stock. The average value and standard deviation of δ13 C and δ15 N of the 6 samples of undetermined culture are -11.62±0.43 ‰ and 8.18±0.16 ‰ . In the scatter plot, five of them(M32,M32:D,M251,M80,M41:A)are in the district of low δ13 C and δ15 N while M272 is different. In the cluster plot, those five samples are clustered together, indicating their big diet difference from that of the Zongri Culture samples. It could be concluded that M272 belongs to the Zongri Culture, while M251,M32:D,M80 and M41:A do not, which completely accords with the results from other archaeological means. The dietary analysis can be thus a reference to distinguish different cultures. The palaeodietary trend reveals that C4 plants was the main food of the inhabitants through out the history of the Zongri Culture, and its proportions in diet increased gradually from the first period to the third, respectively of 81.8 ％ , 84.4 ％ , and 85.7 ％ (Fig.3a). On the contrary, δ15 N value decreased with the periods, of 8.72 ‰ , 8.47 ‰ , and 8.10 ‰ (Fig.3b) respectively, revealing a less and less consumption of meat. The changes of C4 plant prototion and δ15 N value indicate the gradually enhanced dry farming and declined activities of hunting and fishing, which is contradicting the former proposal that the Zongri Culture tended to develop pasturage but agrees that the millet-planting agriculture was still the main economic pattern of the inhabitants.