Abstract: An improved volume rendering algorithm called ISWA,based on Shear-Warp method,is proposed in this paper.It is convenient and meaningful to pre-specify the transfer function for volume rendering based on the boundary model and interactive operation.In addition,to improve the reconstruction effect of medical images,the parameters of the transfer functions are corrected during the re-sampling process using the intermediate slice interpolation method.Experiments demonstrate the good performance of the proposed method.