Abstract Background It is believed that deposition of amyloid beta (Aβ) in the brain is the central pathological changes of Alzheimer’s disease (AD), which triggers a series of pathological processes. However, the relationship between dyslipidemia and AD is uncertain. Considering the peripheral Aβ levels are related to brain Aβ deposition, we explore the relationships between blood lipids and plasma Aβ. Methods Participants who lived in the selected village of Xi’an for more than 3 years were enrolled, aged 40–85 years (n = 1282, 37.9% male). Fasting blood lipid, plasma Aβ levels, basic information and living habits were measured. Multiple linear regressions were used. Results In total population, blood lipids were not associated with plasma Aβ. After stratified by blood pressure, serum total cholesterol (TC) and low-density lipoprotein (LDL-c) were positively associated with plasma Aβ42 levels (βTC = 0.666, PTC = 0.024; βLDL-c = 0.743, PLDL-c = 0.011, respectively) in normal blood pressure. LDL-c was negatively associated with plasma Aβ40 levels (β = − 0.986, P = 0.037) in high blood pressure. Conclusion Elevated plasma Aβ42 levels are associated with higher TC and LDL-c in normal blood pressure. Elevated plasma Aβ40 levels are associated with lower LDL-c in high blood pressure. This indicated that the relationships between blood lipids and plasma Aβ were confounded by blood pressure.