Abstract: Objective:To investigate the feasibility of reducing the radiation dose and scanning time of patients with novel coronavirus pneumonia by setting the parameters of 64-slice spiral CT. Methods:Prospective selection of patients who needed to be screened for novel coronavirus pneumonia was randomly divided into a large pitch group and a control group according to the scan time, with 16 cases in each group. The large-pitch group chose 1.375:1, and the control group chose 0.984:1.The image quality of lung markings, bronchus, and mediastinal structure, objective data of thoracic aorta, erector spinae, bilateral lung parenchyma, and radiation dose were evaluated and analyzed. Results:32 cases of images meet the requirements of imaging diagnosis. The artifact and lung markings scores were significantly different(P<0.05). The CT values of the right lung were-804.62 ±45.43 and(-852.12 ±28.13) HU, and the CT values of the left lung were(-808.13 ±37.74) HU and(-858.77 ± 19.95) HU, demonstrates statistically significant(P<0.05). The scanning time of the two groups was(2.14 ±0.15) s and(3.14 ±0.28) s, respectively, which was statistically significant(P<0.05). The volume CT dose index(CTDIvol) recorded by the two groups was(7.88 ±0.89) HU and(11.17 ±1.08) HU, and the dose length product(DLP) was(279.14 ±36.33) HU and(387.25 ±47.86) HU. Both were statistically significant(P<0.05). The effective dose(ED) were(3.91 ±0.51) HU and(5.42 ±0.67) HU, respectively, with statistical significance(P<0.05). Conclusion:The use of large-pitch scanning in CT screening of patients with novel coronavirus pneumonia can reduce the radiation dose, significantly shorten the scan time, and reduce the radiation dose received by patients and the risk of infection by radiation technicians without affecting the diagnosis of lesions. It as practical significance, and needs to be further promoted and verified.