Objective to study the dual-source CT low-dose technology in the application of CT examination in patients with suspected chest lesions. Methods Selection in November 2013 to November 2014 in our hospital for inspection of 161 patients with suspected chest lesions, according to the order of patients in the hospital can be divided into 7 groups, each group of 23 cases, the 7 groups patients respectively using conventional pipe electricity flow 110 mAs and low electrical flow 105, 100, 95, 90, 85, 80 mAs measurement, comparison between groups in patients with pulmonary artery bifurcation plane the signal-to-noise ratio of pulmonary artery, pulmonary artery - sma vertical contrast to noise ratio, the descending aorta signal-to-noise ratio, the descending aortasma vertical contrast to noise ratio, the subjective image quality score and lesion detection. Results With the reduction of radiation dose, the signal-to-noise ratio of the pulmonary artery and the descending aorta gradually reduced (P<0.05). Each image quality score and decreased with the decrease of the bulb electricity flow (P<0.05), 80 mas electric flow of low duct lesion detection rate of 81.25% from the rest of the group was significantly lower (P<0.05). Conclusion Dual-source CT low-dose technique can in suspected lesions in patients with chest CT examination to give accurate judgment, can effectively reduce the radiation damage to human body, suggested that dual-source CT examination with 85 mas reference pipe flow, both can obtain accurate diagnostic images clearly and can significantly reduce the radiation dose