The mother-infant relationship has long been considered as an important topic both in the fields of anthropology and psychology. Anthropologically, the nutritional metabolism of the mother and infant during pregnancy is closely related to their long-term health status; while from the psychological perspective, this relationship is important to the formation of consciousness, psychological development, identity of the children, which is also reflected in the social and cultural constitution. Exploring mother-infant nexus of the ancient populations provides an approach to the understanding of the social life and ideology of our past. This paper presents a study of four mother-infant joint burials from the Jiayi Cemetery, a Bronze-Early Iron Age cemetery from Northwest China, using the methods from human osteoarchaeology, archaeothanatology and clinical medicine. Biological data of the human remains, and the distribution of these skeletons were collected and analyzed. Results show that all the adult individuals were females of childbearing age, and the infant individuals were in their perinatal periods. Three infants were put between the arms and bodies of the female individuals, while another fetus (M224:2) was found between the adult’s pelves. These findings indicate that the former mothers and infants died after childbirth, while the latter group seemed to have died together during childbirth. Combining the previous bioarchaeological research, malnutrition and infectious diseases were common among the Jiayi population, which could be an explanation for their high risk of death. These burials also reflect the Jiayi people’s understanding of the bond between mother and child, and their belief in 'soul'. Burying the mother and infant together is a way not only to show the respect for the dead, but also to comfort the living.