Abstract: On the basis of analysis of flat panel detector correction methods and the residual causes of ring artifacts in cone-beam CT (CBCT), a simple correction method for CBCT ring artifacts based on air scan is proposed.Firstly, an air scan and measured object scan are performed using the same parameters in the same CBCT system.And then a series of slice images are reconstructed, respectively.Finally, the air slice images are subtracted from the corresponding slice images of the measured object to achieve the correction of the residual ring artifacts, at the same time playing a certain role in noise reduction.Experimental results demonstrate the feasibility and effectiveness of this method.