Abstract: According to the characteristics of the spatial scalable video coding, a fast intra encoding algorithm is proposed for the enhancement layer.Firstly, according to the base layer and the adjacent macroblock, the current macroblock mode selection is proposed, and the residual prediction is applied to increase the coding speed.Then direction mode selection for Intra16 and Intra4 is proposed.In Intra16 mode, the texture of macroblock is applied to predict the possibility of each of direction mode, and the encoding is carried out according to the value of the possibility in a decreasing order, combined with the residual prediction to accelerate the encoding speed;In Intra4 mode, the possible direction mode of the current sub-block and its possibility value is predicted according to the base sub-block and the adjacent sub-block, combined with early zero-block detection for a further improvement on the coding speed.The experimental results show that the computational complexity of the algorithm is reduced by 75% on average compared with the standard method, with only negligible coding loss and bit-rate increases.