Objective To evaluate the application of three-dimensional (3D) imaging device to colonoscopy. Methods A total of 60 patients who underwent painless colonoscopy in Beijing Friendship Hospital, Capital Medical University from November to December, 2019 were enrolled and divided into 2 groups according to random code. Each patient underwent colonoscopy twice, while 2D colonoscopy was used for cecal intubation. Thirty patients were assigned to the experimental group (primary withdrawal used 3D colonoscopy, and secondary withdrawal used 2D colonoscopy), and 30 others to the control group (primary withdrawal used 2D colonoscopy, and secondary withdrawal used 3D colonoscopy). The detection of polyps, the withdrawal time, operating experience, image quality and complication were evaluated in the two groups. Results The polyp detection rate at the first colonoscopy in the experimental group was 77.3% (17/22), which was higher than 43.5% (10/23) in the control group (χ2=5.351, P=0.021). Ten operators in the experimental group had dizziness, while the operators in the control group had no dizziness (P=0.001). There were no significant differences between the two groups in the polyp diameter [0.50 (0.70) cm VS 0.30 (0.20) cm, U=57.000, P=0.170], withdrawal time (4.6±1.5 min VS 5.2±1.9 min, t=-1.189, P=0.239) or image quality (27 cases with 3 points in the identification of lesion nature, and 28 cases with 3 points in the identification of duct both in the two groups, P=1.000) at the first colonoscopy. No complication occurred in either group. Conclusion Application of 3D imaging device is feasible for colonoscopic polyp detection, and it can be used in clinical practice.