Intra4×4 mode decision has correlation between enhancement layer and base layer in scalable video coding (SVC). In this paper, a new intra mode decision algorithm is proposed based on this correlation and the proximity of prediction directions of nine Intra4×4 prediction modes. This method is used in enhancement layer to decrease the mode numbers in enhancement layer. Experiments show that the proposed algorithm can save 27.52% encoding time on average with negligible PSNR change and small bit-rate loss.