Objective: To evaluate the effect of average heart rate,heart rate variability and selection of reconstruction phase on quality of coronary angiography image by 64-slice spiral computed tomography (CT). Methods: Fifty-one patients with suspected coronary artery disease or coronary atherosclerosis underwent CT coronary angiography using Siemens 64-slice spiral CT. Raw helical CT data were reconstructed at 0%~95% of the cardiac cycle with increments of 5% by Siemens Syngo MMWP VE23A reconstruction processing work station. The reconstruction included volume reconstruction,multi-planar reconstruction,maximum intensity projection and curved planar reconstruction. The 51 patients were divided into several groups according to the average heart rate and heart rate variability,and then select the optimal reconstruction phase and evaluate the quality of the image. Results: The optimal reconstruction phase of the coronary artery in < 65 beats per min group was 60%~75%. The optimal reconstruction phase of the coronary artery in 65-70 beats per min group was 65%~70%. The optimal reconstruction phase of the coronary artery in > 70 beats per min group was 30%~40%. There was a negative correlation between heart rate,heart rate variability and image quality score(P < 0.05). Conclusion: The appropriate control of heart rate and heart rate variability,and the correct selection of reconstruction phase could improve the image quality of coronary angiography.