The invention discloses an H.265 half reversible video information steganography method based on an intra-frame prediction mode. The method comprises insertion and extraction; the insertion part comprises: acquiring an original network video source file and secret information; preprocessing the secret information; selecting an insertion position according to an optimal prediction mode during video coding based on the purpose of no distortion drift and performing insertion modulation, wherein the inserted information is based on the preprocessed secret information, till the tail of the secret information is inserted. The extraction part comprises: acquiring a carrier video transmitted via a network, decoding the carrier video, determining an extraction position according to whether the prediction mode satisfies an extraction condition, and demodulating the inserted secret information till reaching the tail of the information; and recovering the extracted information to obtain the original secret information. The H.265 half reversible video information steganography method overcomes distortion drift of the carrier video due to insertion, has good PSNR (Peak Signal To Noise Ratio), and has the characteristic of half reversibility because recovery of the video carrier is considered when the secret information is extracted.