A method and apparatus are provided for reducing the inter-layer redundancy of a difference signal obtained from an intra-prediction when coding a video using multi-layer structure supporting intra-prediction. The method includes obtaining a first difference block between a block of a first layer and a first prediction block which is used to perform an intra-prediction on the block, obtaining a second difference block between a block of a second layer corresponding to the block of the first layer and a second prediction block which is used to perform an intra-prediction on the block, and obtaining a final difference block between the first difference block and the second difference block.