Abstract: AIM:To investigate the influence of diabetes on the severity assessment of coronary atherosclerotic heart disease (CHD) using diameters of the retina vessels. METHODS: Retina photos were taken in 120 patients who were diagnosed with CHD by coronary arteriography (CAG). Central retinal arteriolar equivalents (CRAE) and central retinal venular equivalents (CRVE) were calculated by Parr-Hubbard formulas, and Gensini scores were obtained. Other cardiovascular risk factors were obtained by questionnaires and venous blood. The influence of diabetes on the relevance between Gensini score and CRAE and CRVE were calculated by covariance analysis, and the influences of other risk factors on the CRAE and CRVE were analyzed by variance and χ2 analysis. RESULTS: Diabetes increased the CRVE in CHD patients but had no obvious effect on CRAE. Diabetes significantly affected the relevance between Gensini score and CRAE, but no such effect was seen between Gensini score and CRVE. Other factors that affected CRAE were age, gender, systolic pressure, diastolic pressure, mean arterial tension, body mass index, current smoking, hypertension, low-density lipoprotein and high-density lipoprotein, whereas the factors that affected CRVE were gender, smoking history, hypertension and HbA1c.CONCLUSION: Diameters of retinal vessels can partly report the severity of CHD, but diabetes and other cardiovascular risk factors should be considered in the severity assessment.