Hypoxia inducible factor (HIF) is a product of tumor cells that plays an important role in protecting tumor cells and adjusting to low oxygen tension through driving the progression and aggressiveness of tumors and changing the growth, angiogenesis, differentiation and metastasis of tumors. Prolyl hydroxylase 3 (PHD3) is a member of PHDs that are induced in hypoxia. Many studies have shown that PHD3 not only can hydroxylate HIF-1α, but also has various other biological functions. Thus PHD3 plays significant roles in suppressing the growth, angiogenesis, differentiation and metastasis of tumors and promoting apoptosis of tumors under hypoxic conditions. It may become a new tumor suppressor gene and also may become a new approach to investigate tumors