Objective:To investigate the imaging quality of CBCT under different exposure parameters and the relationship between subjective and objective evaluation.Methods:CBCT scanners of 6 different suppliers[3D Accuitomo(Morita),i-mCAT(Kavo),5G(NewTom),Smart3D(Beijing Langshi),DCT Pro(Vatech),Vgi(NewTom)]were used to scan the spatial resolution models and head simulators under typical exposure conditions(different device with different tube voltage and current for exposure).The visibility of SedentexCT IQ phantom and anatomical structures generated by different CBCT scanners were compared.For objective evaluation,7 professional evaluators scored CBCT imaging qualities.For subjective evaluation,the resolution(LP/mm)of the images were com-pared among the devices.Results:No significant difference was found by 7 evaluators either intra or inter of the teams.By objective e-valuation,the score of NewTom 5G was 2,that of i-CAT was 5 and that of the others was 4.By subjective evaluation,the LP/mm of i-CAT was 1.8,that of Smart3D was 2.0 and that of the others was 1.0-1.7.The subjective evaluation of image quality obtained un-der different tube voltages and tube currents were significantly different.Conclusion:The subjective and objective evaluations of image quality are approximately consistent.The difference of the subjective image quality may be produced by the different tube voltage and current for exposure.