Abstract： Objective To determine possible causes of ruptures of intracranial aneurysms during the follow-up period.Methods There were a total of 183 cases of unruptured intracranial aneurysms (UIAs) diagnosed between January 2015 and January 2017 at Department of Neurosurgery,the First Affiliated Hospital of Nanchang University.Among them,aneurysm rupture occurred in 4 patients (2.2％) during follow-up,whose clinical and imaging data were retrospectively analyzed.The risk factors of aneurysm rupture were investigated with relative literatures as references.Results Mean age of the 4 patients,including 2 males and 2 females,was 60.5 years.Two patients had medical history of high blood pressure.Multiple aneurysms were found in 2 cases.The sizes of UIAs in this series were all less than 7 mm.The daughter sac was found in 3 UIAs and the growth of aneurysm was observed in 2 patients after rupture.One case underwent complete surgical clipping and the other 3 were received endovascular treatment (complete occlusion in 1 and near-complete occlusion in 2).Post-operative outcomes were favorable in all cases.Conclusion The risk factors for rupture of UIAs might include older age,hypertension,multiple aneurysms and irregular shape,which should be well treated.