Objective To investigate the risk factors of the properties of carotid plaque and the relationship between the carotid plaque properties and the severity of coronary artery disease in patients with coronary heart disease. Methods A total of 127 patients with coronary artery disease confirmed by coronary angiography admitted to our Department of Cardiology or Geriatrics from March 2018 to April 2019 were enrolled in this study. According to the results of carotid artery color Doppler ultrasound, they were divided into unstable plaque group (n=78) and stable plaque group (n=49). The general information, blood indices, Gensini score, and number of lesioned coronary artery were collected, and risk factors affecting the properties of carotid plaque and the relationship between the carotid plaque properties and the severity of coronary artery disease were analyzed. SPSS statistics 22.0 was used to perform the statistical analysis. Student′s t test or Chi-square test was employed for comparison between groups. The risk factors for the properties of carotid plaque were analyzed by binary logistic regression analysis. Results The levels of serum uric acid and homocysteine were (19.87±13.13) and (331.87±60.53)μmol/L, respectively in the unstable plaque group, and (13.40±3.74) and (282.28±49.91)μmol/L in the stable plaque group, with significant differences between the two groups (P<0.05). But no such differences were observed in the levels of fasting blood glucose [(5.76±2.32) vs (5.59±1.79)mmol/L], cystatin C [(0.98±0.24) vs (0.89±0.19)mg/L], serum creatinine[(71.24±14.89) vs (67.43±10.88)μmol/L] and fibrinogen[(3.09±0.73) vs (2.90±0.57)g/L] between the two groups (all P>0.05). The results of binary logistic regression analysis showed serum uric acid was associated with plaque instability (OR=1.020, 95%CI 1.005-1.036; P<0.05). The Gensini score was 41.72±16.26 and 31.80±9.54, and the number of lesioned coronary artery was 1.96±0.79 and 1.51±0.50, respectively in the unstable plaque group and the stable plaque group, with significantly differences between the two groups (P<0.05). Conclusion The increase of serum uric acid level is closely related to the instability of carotid plaque in patients with coronary heart disease. The instability of carotid plaque can be used as an index to predict and evaluate the severity of coronary artery disease in these patients.