Objective To analyze the factors affecting the accuracy of 64 row spiral CT coronary artery imaging in the diagnosis of coronary heart disease with diabetes. Methods To retrospectively analyze 248 cases of patients coronary heart disease with diabetes mellitus who underwent 64 row spiral CT coronary artery imaging and coronary angiography (CAG) examination in our hospital. They were divided into groups according to calcification score, the average heart rate, heart rate, fluctuation and fasting plasma glucose concentrations. different level to the CAG diagnosis as the gold standard, each 64 row spiral CT coronary artery imaging evaluation of coronary artery stenosis degree of 50% or higher sensitivity, specific, positive predictive value, negative predictive value and the diagnostic coincidence rate and statistical analysis. Results (1)64 row spiral CT coronary artery imaging and CAG common development, and evaluation of 2036 segmental coronary segments, 1424 segments of men, 612 segment of women, (2) CAG as the gold standard, 64 row spiral CT coronary artery imaging in the diagnosis of mild degree of calcification group specific, positive predictive value and the diagnosis coincidence rate were higher than in severe calcification group, after statistics analysis, the difference statistically significant (P<0.05). Grouping diagnosis of heart rate (heart rate>70 times/min and heart rate of 70 times/min or less) and heart rate fluctuations group (heart rate fluctuations>15 times/min and heart rate group 15 times/min or less) and fasting plasma glucose group (fasting glucose>10.00mmol/L and fasting plasma glucose group≤10.00mmol/L) or less sensitivity, specific, positive predictive value, negative predictive value and diagnostic coincidence rate had no obvious difference (P>0.05). Diagnosis of male and female specific degree, negative predictive value and the diagnosis coincidence rate had no obvious difference, diagnosis of female sensitivity and positive predictive value is lower than the male group, difference has statistical significance (P<0.05). Conclusion Severe coronary calcification reduce the diagnostic accuracy of CT coronary artery imaging. The imaging way still has high diagnostic accuracy even with high heart rate and heart rate fluctuations; Its diagnostic sensitivity and positive predictive value is lower in female than male. The fasting blood glucose has not effect on the diagnostic accuracy.