Abstract: According to the property of the low-dose CT projection noise,this paper propose a wavelet-transform based low-dose CT projection BM3D Filtering(Block-Matching and 3D filtering)technique.For the proposed method,first,low-dose projection data is decomposed by Haar-wavelet transform after Anscombe transform.And then the efficient BM3D algorithm is performed separately in the scale coefficient and the wavelet coefficients.Next,the filtered coefficients are transformed orderly by inverse Anscombe transform and inverse Haar-wavelet transform.Finally,the reconstruction image is achieved by the classical filtered back projection(FBP)method.Simulated and clinical data experimental results demonstrate that the proposed method can do well in noise suppression and detail preservation of the reconstructed image.