Metastasis and recurrence is still the main cause of death in cancer. Recent studies have found that the peripheral blood circulating tumor cells (CTCs) may be taken as an important indicator to determine prognosis. In the moment of promoting individualized treatment, CTC detection can help guide the design of more effective clinical treatment options, thereby prolong patients’ life and improve patients’ survival. In this paper, the mechanisms of tumor recurrence and metastasis, and the technological methods of CTC enrichment and identification are reviewed.