Background Intracranial atherosclerosis (ICAS) is a common etiology of ischemic stroke in Chinese patients, probably leading to regional hypoperfusion in the brain. The purpose of this prospective study was to investigate the association between ICAS and poststroke depression in Chinese patients with ischemic stroke. Methods During the study period, a total of 569 patients aged between 40 and 80 years with acute ischemic stroke were consecutively admitted and screened. Patients with a National Institutes of Health Stroke Scale (NIHSS) total score of 15 or higher, with severe cognitive impairment, or with a history of depression before stroke were excluded. Two hundred seven patients with ischemic stroke were consecutively recruited in the study. Depressive symptoms were assessed in the acute stage and 3 months after stroke. Poststroke depression was defined as a score of 8 or higher in the 24-item Hamilton Depression Rating Scale. The evaluation of the magnetic resonance imaging scans focused on infarctions, white matter lesions, brain atrophy, and ICAS. Results In the acute stage of stroke, logistic regression revealed that female sex, NIHSS score at admission, prestroke insomnia, and ICAS were significant predictors of poststroke depression. At 3 months after stroke, prestroke insomnia, the Mini-Mental State Examination score and ICAS were significant predictors of poststroke depression. Conclusions ICAS may be a significant independent predictor of poststroke depression in Chinese patients with ischemic stroke.