Aim To investigate the electroencephalographic characteristics of elderly post-stroke depression(PSD) and affecting factors of depression. Methods 500 cases of elderly stroke patients were selected and divided into PSD group (n=200, including mild group of 61cases, mid group of 85cases and severe group of 54 cases) and non-PSD group (n=300)according to the presence or absence of PSD. The EEG examination was performed onset within 7 d, and EEG amplitude, frequency, α, β, δ, θ wave distribution were observed, the affecting factors of stroke complicated depression in the elderly were analyzed by univariate and multivariate stepwise Logistic regression. Results The rate of EEG abnormality in PSD group (53.00%) was significantly higher than that in non-PSD group (43.67%), and the rate of low-amplitude δ wave (68.00%) was significantly higher than that in non-PSD group (54.00%, P<0.05). The rate of EEG abnormality in severe group (61.11%)was significantly higher than mild group of 32.79%(P<0.05). Univariate analysis showed that the rate of depression in elderly stroke patients with education, hypertension, depression, family relationship, lesion location, eeg characteristics were affecting factors of PSD. Multiple stepwise Logistic regression analysis showed that high educational level, history of hypertension, history of depression, family disagreement, basal ganglia lesion, low amplitude wave and EEG abnormality were independent risk factors for elderly PSD (P<0.05). Conclusions EEG of the elderly PSD shows mainly low amplitude δ wave. Education, hypertension, depression, family relationship, basal ganglia, low amplitude δ wave are closely related to PSD.