Objective To observe the effect of Naoxintong Capsule (NC) on carotid artery vas- cular remodeling (VR) in type 2 diabetes mellitus (T2DM) patients with subclinical vascular disease. Methods A total of 180 T2DM patients with subclinical atherosclerosis (AS) were randomly assigned to the observation group and the control group in the ratio of 1:1 , 90 in each group. All patients took conven- tional hypoglycemic therapy, and the choices of therapeutic drugs and doses were selected according to patients' conditions. Patients in the observation group additionally took NC (3 pills each time, three times per day) , while those in the control group took no interventional drug. The therapeutic course for all was 6 months. The size and nature of bilateral carotid artery plaque were measured before and after treatment using color Doppler ultrasound diagnostic instrument. Bilateral carotid artery intimal-medial thickness (IMT) , plaque area (PA) , total vascular area (TVA) , lumen area (LA) , peak systolic velocity (PSV) , end diastolic velocity (EDV) , vascular resistance index (VRI) , and pulsatility index (PI) were measured. The total plaque score, unstable plaque detection rate, stenosis rate (S) , and refactoring index ( RI) were calculated. Levels of fasting plasma glucose (FPG) , glycated hemoglobin Al c (HbA1 c) , triglyceride (TG) , total cholesterol (TC) , high density lipoprotein cholesterol ( HDL-C) , and low density lipopro- tein cholesterol (LDL-C) were detected. Results Compared with before treatment in the same group, carotid artery IMT and plaque score decreased, levels of TC, TG, LDL-C, FPG, and HbAlc were reduced, PSV, EDV and PI increased, and VRI decreased in both two groups after treatment, with statisti- cal significance (P <0. 05). More obvious effects were shown in decreasing carotid artery IMT, plaque score, PA, and unstable plaque detection rate, reducing levels of TC, LDL-C and VRI, and increasing HDL-C, PSV, and EDV in the observation group, with statistical difference as compared with the control group (P <0. 05). After treatment the reconstruction rate and negative remodeling increased in the control group, with statistical difference as compared with before treatment (P <0. 05). Compared with the control group after treatment, the negative remodeling increased more in the observation group after treatment (X2 =6. 4615, P <0. 05). Conclusion NC could alleviate the carotid artery IMT, reduce and stabilize the plaque, improve blood flow parameters, and delay vascular reconstruction for treating T2DM patients with subclinical vascular disease.