Objective To contrast the radiation dose to patients of 320 row CT coronary artery imaging (CTCA) and coronary angiography(CAG) .Methods 90 patients random sampled with 320 row CTCA were group A .Among of them ,7 patients with cal-cification integral scanning (CI) were A1 group;43 patients with CT coronary artery imaging/cardiac function analysis scanning (CTCA/CFA) were A2 group;40 patients with Prospective scanning (Prospective CTA ) were A3 group;139 patients random sam-pled with CAG were group B .Results Radiation dose had statistically significant between Group A and group B ,A1 and B ,A2 and B ,A1 and A3 ,A2 and A3(P<0 .05) .radiation dose had no statistically significant between Group A3 and group B ,A1 and A2(P>0 .05) .Conclusion In order to reduce the radiation dose to patients ,the prospective CTCA was used in the patients need 320 row CTCA as far as possible .