Objective　The　objective　of　this　study　was　to　investigate　the　changes　of　number　and　function　of　late　endothelial　progenitor　cells　(EPCs)　in　peripheral　blood　of　chronic　obstructive　pulmonary　disease　(COPD)　patients　combined　with　pulmonary　hypertension.　Subjects　and　Methods　The　study　enrolled　120　cases　including　40　non-COPD　and　pulmonary　arterial　hypertension　(PAH)　patients　(non-COPD　group),　40　COPD　non-PAH　patients　(COPD　group),　and　40　COPD　patients　combined　with　PAH　(COPD　+　PAH　group).　Peripheral　blood　mononuclear　cells　were　separated　by　density　gradient　centrifugation,　cultured　for　21　days,　and　then　identified　as　late　endothelial　progenitor　cells.　The　cell　colonies　were　counted.　MTT　assay,　modified　Boyden　chamber　assay,　and　human　fibronectin　plates　were　used　to　measure　the　proliferation,　migration,　and　adhesion　functions　of　the　late　endothelial　progenitor　cells,　respectively.　Results　Compared　with　non-COPD　and　COPD　groups,　the　number　of　peripheral　blood　late　EPCs　in　COPD　+　PAH　group　was　significantly　reduced,　and　the　proliferation,　adhesion,　and　migration　capacities　were　significantly　lowered;　the　differences　were　statistically　significant　(p　＜　0.05).　The　number　and　function　of　late　EPCs　decreased　with　the　increase　of　pulmonary　artery　pressure　(p　＜　0.05).　Conclusion　The　number　of　late　EPCs　in　COPD　patients　combined　with　pulmonary　hypertension　was　reduced,　which　implies　the　impaired　cell　functions.　The　changes　of　number　and　function　were　negatively　correlated　with　the　severity　of　pulmonary　hypertension.