Aim To investigate the relationship between glycosylated haemoglobin (HbA1c) levels and intima-media thickness of the common carotid artery (CCA-IMT) and the predicting effects of HbA1c on CCA-IMT in newly diagnosed type 2 diabetes (T2DM). Methods The CCA-IMT was assessed using non-invasive high resolution B-mode ultrasonography. Age, sex, metabolic parameters including body mass index (BMI), fasting plasma glucose (FPG), HbAlc, serum lipids, blood pressure, 24 h albuminuria (UALB) and CCA-IMT were compared among T2DM without subclinical atherosclerosis (As) (T2DM group), T2DM with subclinical atherosclerosis (As group) and T2DM with clinical atherosclerosis (CHD group). The 156 newly diagnosed T2DM (duration≤1 year) without atherosclerosis received the multifactorial targeted intervention, including taking aspirin and controlling blood glucose, blood pressure, blood lipid and body weight. The differences of metabolic control were analyzed between CCA-IMT progressive group and non-progressive group. Logistic regression analysis was used to disclose the correlation between the CCA-IMT and macrovascular risk factors. Results HbAlc levels were higher in CHD group than those in T2DM group and atherosclerosis group (P<0.01). CCA-IMT had a linear correlation with HbAlc in T2DM patients(r=0.106, P=0.049). After multifactorial intervention for 2 years, △CCA-IMT had a linear correlation with baseline HbA1c (r=-0.189, P=0.024)and △HbA1c(r=0.166, P=0.041). △HbA1c was lower in the CCA-IMT progressive group than those in the CCA-IMT non-progressive group. Logistic regression analysis showed that △HbA1c was closely correlated with CCA-IMT. Conclusions HbAlc level was one of risk factors for CCA-IMT in T2DM. Under the multifactorial intervention for 2 years, baseline HbA1c and △HbAlc may predict the progression of CCA-IMT in patients with newly diagnosed type 2 diabetes.