Objective To explore the value of dual source CT low-dose coronary angiography in the diagnosis of coronary heart disease (CHD). Methods 90 patients with CHD who underwent dual source computed tomography (DSCT) examination were enrolled in the study, and they were randomly divided into low dose group and routine dose group, with 45 cases in each group. The dose parameters [volume CT dose index (CTDIvol), dose length product (DLP), effective dose (ED)], pitch, image quality and image noise were compared between the two groups. Results The scanning process of the 2 groups was smooth, and the CTDIvol, DLP and ED in the low dose group were significantly lower than those in the routine dose group (P<0.05). There was no significant difference between the 2 groups in the ROI area, pitch, evaluable segment, the excellent and good rate of image and image quality (P>0.05). The image noise of low dose group was significantly higher than that of the routine dose group (P<0.05). Conclusion The heart rate has no effect on the retrospective ECG gated scan mode, and the failure rate is low. Reducing the bulb tube voltage and current value also can reach the requirement of image quality, and reduce the radiation dose. DSCT low dose angiography is of great value in the diagnosis of CHD.