Rate distortion optimization (RDO) is one of the key techniques in the f ield of video coding.Either sum of square error (SSE) or sum of absolute difference (SAD) is widely adopted to evaluate distortion in conventional RDO,which fails to achieve high consistency with human visual pe rception.Recently,the structural similarity (SSIM) index has been attracting more and mor e attention as a perceptual visual quality metric for optimizing video codecs.Meanwhile,high efficiency video coding (HEVC) as the e merging video coding standard creates many new opportunities and challenges.In this paper,we propos e a method of structural similarity index based RDO for HEVC intra coding.Firstly ,an SSIM-based distortion computational method is designed according to the coding tree unit (CTU) structure of HEVC.Secondly,a quantizer-derived rate-quantization step (R-Δ) model and a statistical analysis-based distortion-quantization parameter (DSSIM-QP) model are presented for Lagrange multiplier calculation.Finally,the model para meters are estimated based on multi-QP optimization.Extensive experimental results sh ow that compared with traditional RDO approach of HEVC,for the same SSIM score,the proposed approach can achieve an average rate reduction of about 8.4% and 13.9% with 3% and 2% encoding time increasement,respectively for fixed QP and multi-QP optimizations on all intra coding configure.