Background: The uterine endometrium is a tissue that needs sufficient energy to support its active physiological function, the damage of which is responsible for intrauterine adhesion. In this study, we investigated the evidence that mitochondrial transfer is involved in endometrial repair and explored the effects and possible mechanism of mitochondrial transfer.Methods: The study was approved by the regional ethics committee of Ningbo Women and Children’s Hospital (Date: 12/3/2021/No: EC2021-M004). Endometrial stromal cells were pretreated with hypoxia and cocultured with human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) in vitro. Confocal imaging was used to assess mitochondrial transfer between the cells. The proliferation and ATP production of endometrial stromal cells were detected to evaluate the physiological function of the cells.Results: We found that coculture of hUCB-MSCs and endometrial stromal cells partially restored the proliferation and ATP production of hypoxic cells. Mitochondrial transfer was observed from hUCB-MSCs to hypoxic endometrial stromal cells. This process can be blocked by hUCB-MSCs pretreated with carbenoxolone disodium (CBX), which can block TNT connection formation.Conclusions: The mitochondria of stem cells could be transferred completely into hypoxic endometrial stromal cells, partially restoring the proliferation of injured cells in vitro. This process is proactive.Trial registration: The study was approved by the regional ethics committee of the Ningbo women and Children’s Hospital (Date: 12/3/2021/No: EC2021-M004).