A video decoding method, comprising: decoding information on a quantization matrix; reconstructing a quantization matrix based on the information on the quantization matrix; generating a residual block for a current block based on the reconstructed quantization matrix; generating a prediction block for the current block; and reconstructing the current block based on the residual block and the prediction block, wherein the residual block is generated by performing inverse-quantization on a quantized coefficient of the current block using the reconstructed quantization matrix, wherein the prediction block is generated by performing intra prediction, wherein the information on the quantization matrix includes information indicating a prediction method of the quantization matrix and further includes, based on the information indicating a prediction method of the quantization matrix, information representing a difference value between quantization matrix coefficients, wherein the reconstructing of the quantization matrix is characterized by including deriving a quantization matrix coefficient by using the information representing a difference value between the quantization matrix coefficients; and arranging the quantization matrix coefficients in the quantization matrix by up-right diagonally scanning the quantization matrix coefficients, wherein the up-right diagonally scanning arranges the quantization matrix coefficients along every up-right diagonal lines in the quantization matrix one by one from top-left to bottom-right direction, and starting from a lower-left position to an upper-right position for each up-right diagonal line. decoding information on a quantization matrix; reconstructing a quantization matrix based on the information on the quantization matrix; generating a residual block for a current block based on the reconstructed quantization matrix; generating a prediction block for the current block; and reconstructing the current block based on the residual block and the prediction block, wherein the residual block is generated by performing inverse-quantization on a quantized coefficient of the current block using the reconstructed quantization matrix, wherein the prediction block is generated by performing intra prediction, wherein the information on the quantization matrix includes information indicating a prediction method of the quantization matrix and further includes, based on the information indicating a prediction method of the quantization matrix, information representing a difference value between quantization matrix coefficients, wherein the reconstructing of the quantization matrix is characterized by including deriving a quantization matrix coefficient by using the information representing a difference value between the quantization matrix coefficients; and arranging the quantization matrix coefficients in the quantization matrix by up-right diagonally scanning the quantization matrix coefficients, wherein the up-right diagonally scanning arranges the quantization matrix coefficients along every up-right diagonal lines in the quantization matrix one by one from top-left to bottom-right direction, and starting from a lower-left position to an upper-right position for each up-right diagonal line.