Objective To conclude the application value of dual-source single photons CT with low dose and low -dose contrast agent in chest aortic lesions. Methods Patients suspected aortic dissection in clinical are designed to do dual-source CT angiography, using big pitch scanning solutions or retrospective gating standard scanning technology to scan randomly. Then to observe and analyze the aortic disease in chest and abdomen,with or without dissection, the location and number of interlayer crevasse, the scope of tear, diaphragm, whether the main functional vascular are involved, with or without intramural hematoma, penetrating ulcer and aneurysm. At last, contrast the differences among the image quality, radiation dose and dosage of contrast agent of the two scanning modes. Results Both ways can show the location and number of interlayer crevasse, diaphragm,the scope of tear, whether the main functional vascular are involved. Group A and group B have no significant differences in scanning ranges. The image quality of reconstruction and reorganization of the two groups both reach the optimization criteria. Scanning time of group A is about (1.37±0.19)s, group B is about (14.23±2.01)s, Radiation dose of group A is (4.09±0.88)mSv, group B is (15.95±0.99) mSv. Dosage of contrast agent of group A is (55±5)ml, group B is (85±5)ml, So significant differences between the two groups can be seen. Conclusion The scanning scheme of Dual-source photons CT with big pitch, low radiation dose, and low contrast agent has more advantages in the chest aorta angiography examination.