Abstract: Objective: To explore the value of serum β amyloid protein (Aβ) and tau (tau) protein in early diagnosis of subcortical ischemic vascular dementia (SIVD). Methods: ELISA method was used to detect the levels of serum Aβ38,Aβ40,Aβ42,tau protein and excessive phosphorylated tau protein (p-tau) in 38 patients with SIVD,42 patients with mild cognitive impairment accompanied by subcortical vascular features (MCI-V) and 36 controls. Results: The Aβ40 level of SIVD group was significantly higher than that of the other two groups (P<0.01),and the Aβ40 level of MCI-V group was higher than that of the controls (P<0.05); The levels of Aβ38 and Aβ42 did not differ among the three groups (P>0.05). The tau level of SIVD group was significantly higher than that of the other two groups (P<0.01),and the tau level of MCI-V group was higher than that of the controls (P<0.05). The p-tau level of SIVD group was significantly higher than that of the MCI-V group and the controls (P<0.05). Conclusions: The levels of the serum Aβ40 and tau protein may act as meaningful biomarkers in early diagnosis of SIVD.