Abstract： Objective To investigate the relation between carotid atherosclerosis(CAC) and blood glucose fluctuation in patients with type 2 diabetes mellitus (T2DM). Methods 73 diabetics and 15 normal subjects were divided into three groups：T2DM with CAC(n=38),T2DM without CAC (n=35) and normal control(n=15). The fluctuating feature of 72 hours blood glucose were recorded by continuous glucose monitoring systems(CGMS) and the insulin resistance index (InRI) was compared. ResultsIn diabetic patients with CAC versus with NCAC, the blood glucose fluctuant coefficient (BGFC),mean amplitude glycemic excursions(MAGE) and InRI were significantly higher(P<0.05).In CAC group,BGFC,MAGE and InRI were positively correlated with IMT,and BGFC and MAGE were positively correlated with the InRI (all P<0.05). Conclusions There is a correlation between the blood glucose fluctuation and CAC in patients with T2DM