— The Lagrangian technique proves to be an effective way in Rate-Distortion optimization for hybrid video coding. In this paper, an new Lagrange multiplier selection method for Intra-Frame coding is presented. Based on Laplacian distribution, the variance of transformed residual coefficients is introduced into the rate and distortion model, so that the proposed method is able to adaptively optimize the encoding process for different types of videos. It outperforms the algorithm used in the reference software of H.264/AVC, especially for computer animations and videos with small movements. According to the simulations, a gain up to 0.3 dB was achieved.