Objective: To explore application of different tube voltage-tube current scanning protocol in combination with KARL iterative reconstruction in CT chestscanning for coronavirus pneumonia screening. Methods: The study prospectively enrolled 120 patients with fever subjected to CT chest scanning, who were randomly assigned to groups exa-mined with different scanning protocols: 120 kV tube voltage and automatic tube current modulation with 60 mAs effective tube current (Group A); 120 kV tube voltage and 30 mA fixed tube current (Group B); 100 kV tube voltage and automatic tube current modulation with 60 mAs effective tube current (Group C); 100 kV tube voltage and 30 mA fixed tube current (Group D). The traditional FBP algorithm reconstruction and KARL iterative reconstruction were adopted in the study. The comprehensive image quality was evaluated subjectively based on noise and artifacts. Images reconstructed with FBP algorithm and KARL iterative reconstruction were compared by Wilcoxon test and Kruskal-Wallis test. The image noise within the regions of interest was measured, and the radiation dosage of each protocol in different groups was calculated. Radiation dosage and image noisefor each group were compared with t-test and ANOVA analysis. Results: The radiation dosage of group A, B, C, D were 2.5±0.4, 1.2±0.1, 1.6±0.2 and 0.8±0.1 mSv respectively. The lower tube voltage and tube current decreased the radiation dosage significantly (F=256.316, P<0.001). Image processed with KARL iterative reconstruction had lower noise and better subjective image quality than those treated with FBP reconstruction (P<0.05). At lower radiation dosage, the image acquired with tube voltage of 100 kV and a fixed tube current of 30 mA and processed by KARL iterative reconstruction achieved a score of 4.0 for overall subjective image quality. Conclusion: Compared with FBP reconstruction, KARL iterative reconstruction might reduce noise and improve image quality. With lower radiation dosage, the CT chest scanning protocol with a tube voltage of 100 kV and a fixed tube current of 30 mA in combination of KARL iterative reconstruction is optimum choice for novel coronavirus pneumonia screening.