The culture of Rong people embedded in ancient diverse Chinese history. However, little literature contexts and discoveries have been found to study their subsistence patterns. The archaeological excavations of the Rong people’s cemeteries in the Zhaitouhe and the Shijiahe in Huangling, Yan’an, Shaanxi Province, provided significant archaeological evidence for understanding the social life of the Rong people in Guanzhong region. This study is carried out by human bones unearthed from burials to discuss the diet pattern of the ancient residents which reveals the economic pattern. The carbon and nitrogen stable isotopic analyses indicates that the food habits of people from Shijiahe and Zhaitouhe are similar. The plant foods consist of C₄ herbaceous plants which mainly comprised broomcorn and foxtail millet. Two samples of individuals were mainly fed on meat food, while the others consumed less meat resources. And there is no gender difference on diet pattern. The diet pattern of the Qin people was similar to those ancestors in the early and middle period in the Shijiahe cemetery. The present archaeological discoveries and cultural contexts show that ancestors of the Zhaitouhe and Shijiahe cemeteries formed an economic pattern of the mixture by agriculture and rearing livestock by assimilating the agricultural culture of Guanzhong region based on the local natural environment.