Objective：The current study aims to investigate the effect of fat mass and obesity associated protein(FTO)on the migration of hypoxia-inoluced pulmonary artery smooth muscle cells(PASMC). Methods：MPASMC was cultured in vitro. The hypoxia model of MPASMC was established in a three -gas incubator(37℃，1%O₂，5%CO₂). The expression of FTO protein was detected by Western blot. FTO overexpression and knockdown plasmids were transfected into MPASMC to over-express or inhibit FTO expression， respectively. Cell wound healing assay was used to detect cell migration ability. Results：The expression of FTO protein in MPASMC after hypoxia culture was significantly down-regulated. Wound healing assay indicated that MPASMC migration was accelerated after hypoxia culture and was significantly slowed down after FTO overexpression in MPASMC. Knockdown FTO expression in MPASMC in normoxia showed a“pro-migration”phenotype similar to hypoxic culture. Conclusion：Under hypoxic conditions，the expression of FTO protein is down-regulated in MPASMC and the cells migration ability is enhanced. FTO may be a key regulator of MPASMC migration.