Background Intra-cerebral hemorrhage (ICH) is a devastating complication that can result from superficial temporal artery-middle cerebral artery (STA-MCA) bypass in patients undergoing treatment for steno-occlusive cerebrovascular disease (CVD). There is a clinical need to find the possible risk factors to prevent ICH, as it is a significant cause of mortality and morbidity. The aim of the study was to investigate the factors associated with delayed ICH after STA-MCA bypass in patients with steno-occlusive CVDs. Methods We retrospectively analyzed the records of 163 patients seen from 2002 to 2011 with STA-MCA bypass for steno-occlusive cerebrovascular diseases at the Department of Neurosurgery, Xuan Wu Hospital, Beijing. Demographic and clinical data, including age, gender, vascular risk factors, preoperative syndrome, preoperative National Institutes of Health Stroke Scale (NIHSS), ipsilateral ischemic lesions, classification of steno-occlusive CVDs, donor branches of STA, graft patency, postoperative hypertension, and postoperative-increased MCA velocity were recorded and analyzed. Binary Logistic regression served to identify factors associated with delayed ICH after STA-MCA bypass. Results We identified 8 (4.9%) patients with delayed ICH after STA-MCA bypass. Patients with hypertension, preoperative stroke, ipsilateral ischemic lesions, postoperative hypertension and postoperative-increased MCA velocity were significantly more prone to experiencing delayed ICH after STA-MCA bypass. Logistic regression analysis shows ipsilateral ischemic lesions, postoperative hypertension, and postoperative-increased MCA velocity remained independent predictors for delayed ICH after STA-MCA bypass. Conclusion Despite the varied associated factors in patients with steno-occlusive CVDs, ipsilateral ischemic lesions, postoperative hypertension, and postoperative-increased MCA velocity could be associated with delayed ICH after STA-MCA bypass.