Objective To investigate the application value of low-dose spiral CT(LDCT) scanning in high-risk population screening of lung cancer.Methods A total of 1 071 cases of LDCT lung scanning(observation group) and 350 cases of conventional dose CT lung scanning dose(control group) from October 2015 to May 2017 were performed the comparison on mean irradiation dose,lesion occurrence rate and diagnostic accuracy.Results The computed tomographic dose index(CTDI) in the observation group was(0.74±0.28)mSv;the excellent image quality rate was 95.42 ％;the positive detection rate was 43.60 ％ (467/1 071);13cases(1.21 ％)were confirmed as lung cancer by pathology.The average CTDI in the control group was(14.46 ± 4.21)mSv;the excellent image quality rate was 98.85 ％;the positive detection rate was 45.1 ％ (158/350);5 cases(1.43％) were confirmed as lung cancer by pathology.The average radiation dose and image quality showed statistically significant difference between the two groups (P＜0.05),and the positive detection rate and diagnostic rate of lung cancer had no statistical difference between the two groups (P＞0.05).Conclusion LDCT scan has good image quality,can significantly reduce the subject's irradiation dose without affecting the detection of lung lesions and lung cancer occurrence rate.