Abstract: Tumor dormancy is a stage of tumor development. In this stage， patients don't exhibit significant clinical symptoms. Tumor dormant cells may arise in early stage of tumor development， micrometastases period and minimal residual. The tumor dormant cells can switch between the quiescent stage and proliferative stage， which is considered the cause of tumor metastasis and recurrence. However， the mechanism of this switch is still largely unknown. The elements involved in the switch regulation include unique expression patterns， immune response， and a variety of factors and signaling pathways in the microenvironment. Further study of tumor dormant cells may provide a therapeutic strategy for tumor metastasis and tumor recurrence， which is of great significance to clinical activity and research.