Provided is a method for accelerating coding and decoding of an HEVC video sequence. The method includes following steps: an original video stream is decoded, a LCU and a PU1 are extracted, and the complexity of the PU1 is calculated; a block size division is performed; a quantization step QP1 of the original video stream is recorded; the decoded video stream is recoded, a quantization step QP2 of the recoded stream is set, and a CU2 of a previous frame of a frame to be coded and a CU3 of coded frames 1˜N−1 are extracted; a coding unit of a frame currently being coded is obtained; a final prediction unit mode is determined according to the PU1; a division mode of the coding unit of the frame currently being coded is determined according to a depth information category of the coding unit of the frame currently being coded.