Objetive To evaluate the carotid artery stiffness of acquired immune deficiency syndrome (AIDS) and analyze the mechanism and influence factors. Methods Fifty cases of AIDS patients and Fifty healthy people were enrolled in this study according to the principles of randomize and control. Quantitive inter-media thickness (QIMT) and quantitive artery stiffness (QAS) technique were employed to evaluate the inter-media thickness (IMT) and stiffness of right carotid artery. The parameters included IMT, compliance coefficent (CC), stiffness β (β), and pulse wave velocity (PWV). Unpaired t test was used to compare the parameters between two groups, and Pearson correlation analysis was used for linear correlation analysis. Results There were no statistically difference of carotid artery IMT between two groups [(0.569±0.095) mm vs (0.512±0.114) mm, P>0.05]. There was statistically difference of stiffness parameters (CC,β, PWV) between two groups [(0.59±0.21) mm2/kPa vs (1.04±0.41) mm2/kPa, 13.01±6.10 vs 8.14±1.37, (8.70±1.65) m/s vs (6.81±1.37) m/s, all P<0.05]. There was statistically signification association between HIV-infection time and CC,β, PWV ( r value was-0.575, 0.380, 0.417, all P<0.05 ), but there was no association between HIV-infection time and IMT( r value was 0.191, P>0.05 ). There was no statistically signification association between IMT, CC,β, PWV and CD4+, CD8+T cell count (r was 0.000, 0.012,-0.093,-0.097, 0.096, 0.012, 0.056, 0.024, all P>0.05). Conclusion The carotid artery stiffness of AIDS patients is reduced. HIV may play a role in the development of artery stiffness in AIDS patients.