To investigate whether angiopoietin-1 (Ang-1) could regulate the endothelial progenitor cells (EPCs) survival and the effect of accelerating intra-aneurysmal organization and occlusion of the aneurysm neck. EPCs were isolated from Wistar rats. EPCs were cultured and transfected with lentivirus-Ang-1-endothelial progenitor cells (Ang-1-EPCs) and lentivirus-NC-endothelial progenitor cells (NC-EPCs). The effects of Ang-1 on viability and functioning of EPCs were explored via tube formation, migration, and MTT (3-[4,5-dimethylthiazolyl-2]-2,5-diphenyltetrazolium bromide) assays. Eighteen Wistar rats were randomly allocated into 3 groups. Eighteen bare coils were inserted into the ligated external carotid artery (ECA) sacs of rats. The ECA sacs were removed 2weeks after the coils were implanted and examined by histology assay. Ang-1 significantly promoted EPCs tube formation, migration, and proliferation ability invitro. Histology analyses revealed that the organized areas in the ECA sacs in the Ang-1-EPCs group are higher than NC-EPCs group and control group at 2weeks. Immunofluorescence revealed that organized tissues were characterized by an accumulation of cells positive for α-smooth muscle actin-positive cells in aneurysm sacs. Overexpression of Ang-1 enhanced the tube formation, migration, and proliferation ability of EPCs. Ang-1 gene-modified EPCs accelerated organization within the aneurysms and occlusion of aneurysm neck. Transplantation of Ang-1-transfected EPCs may be a new method for the treatment of aneurysm.