Our study assessed the association between blood lipids and cognitive function in patients with T2DM, we found that serum apolipoprotein A1 was independently associated with cognitive impairment in patients with T2DM, but not TC, TG, HDL-C, LDL-C, and apolipoprotein B. The current findings suggest increased serum apolipoprotein A1 may be considered as a risk factor of cognitive impairment in patients with T2DM. Here, APOB is linked to type 2 diabetes mellitus.