Aim To compare the differences of coronary artery plaque distribution and extent of coronary artery disease between symptomatic patients with and without diabetes （DM）. Method 263 patients with definite and suspected coronary artery disease （CAD） were divided into diabetes （n92） and non-diabetes （n171） group according to the history of diabetes, all of them accepted dual-source computed tomography, and then coronary plaques （mixed, calcified, non-calcified plaques） were counted. Results DM patients showed a higher coronary artery calcification than non-DM in left anterior descending branch （LAD） （P0.007）, right coronary artery （RCA） （P0.041） and total scores （P0.027）. DM patients had more coronary artery plaques （P<0.001） than non-DM patients, mainly mixed plaques （P<0.001） and non-calcification plaques （P0.045）. DM patients had higher mean number of diseased coronary arteries （P<0.001） and obstructive coronary plaques （P<0.001） than non-DM patients. Conclusion Symptomatic DM patients have a higher prevalence of obstructive coronary artery disease and serious extent of calcification than non-DM patients And they are more likely to have higher coronary plaque burden, mainly mixed and non-calcification plaques. But future studies are needed to verify our findings.