A video coding method, comprising: generating a second order prediction flag, sop_flag, for a coding block; when the value of sop_flag indicates that the coding block needs second order prediction, generating a sub second order prediction flag, sub_sop_flag for at least one sub-block of the coding block, wherein the sub second order prediction flag of the sub-block is configured to indicate whether second order prediction is performed on the sub-block; performing second order intra-frame prediction according to the second order prediction flag of the coding block and the sub second order prediction flag of the at least one sub-block of the coding block to obtain a prediction image; obtaining a prediction residual according to the prediction image, and coding the prediction residual; and performing entropy coding on the second order prediction flag of the coding block and the sub second order prediction flag of the sub-block of the coding block, writing coded flags into a bit stream, and sending the bit stream to a decoding end; wherein if the value of sop_flag is 1, it indicates that second order prediction is performed on at least one sub-block of the coding block; and wherein if the value of sub_sop_flag is 0, it indicates that no second order prediction is performed on the corresponding sub-block of the coding block; if the value of sub_sop_flag is 1, it indicates that second order prediction is performed on the corresponding sub-block of the coding block; wherein the coding block is a macroblock, and the size of the macroblock comprises 16 x 16, and the sub-block of the coding block is a sub-block of the macroblock, and the size of said sub-block of the macroblock comprises 8 x 16 or 8 x 8, further comprising: generating, for the sub-block of the coding block, on which second order prediction is performed, a corresponding prediction second prediction mode flag, pred_sp_mode_flag, which is used to perform second order prediction, wherein the pred_sp_mode_flag indicates whether a predicted mode is used as the second order intra-frame prediction mode. generating a second order prediction flag, sop_flag, for a coding block; when the value of sop_flag indicates that the coding block needs second order prediction, generating a sub second order prediction flag, sub_sop_flag for at least one sub-block of the coding block, wherein the sub second order prediction flag of the sub-block is configured to indicate whether second order prediction is performed on the sub-block; performing second order intra-frame prediction according to the second order prediction flag of the coding block and the sub second order prediction flag of the at least one sub-block of the coding block to obtain a prediction image; obtaining a prediction residual according to the prediction image, and coding the prediction residual; and performing entropy coding on the second order prediction flag of the coding block and the sub second order prediction flag of the sub-block of the coding block, writing coded flags into a bit stream, and sending the bit stream to a decoding end; wherein if the value of sop_flag is 1, it indicates that second order prediction is performed on at least one sub-block of the coding block; and wherein if the value of sub_sop_flag is 0, it indicates that no second order prediction is performed on the corresponding sub-block of the coding block; if the value of sub_sop_flag is 1, it indicates that second order prediction is performed on the corresponding sub-block of the coding block; wherein the coding block is a macroblock, and the size of the macroblock comprises 16 x 16, and the sub-block of the coding block is a sub-block of the macroblock, and the size of said sub-block of the macroblock comprises 8 x 16 or 8 x 8, further comprising: generating, for the sub-block of the coding block, on which second order prediction is performed, a corresponding prediction second prediction mode flag, pred_sp_mode_flag, which is used to perform second order prediction, wherein the pred_sp_mode_flag indicates whether a predicted mode is used as the second order intra-frame prediction mode. generating, for the sub-block of the coding block, on which second order prediction is performed, a corresponding prediction second prediction mode flag, pred_sp_mode_flag, which is used to perform second order prediction, wherein the pred_sp_mode_flag indicates whether a predicted mode is used as the second order intra-frame prediction mode.