A picture prediction method includes receiving a bitstream, parsing the bitstream to obtain a prediction mode of a current block, when the prediction mode of the current block is a combined intra and inter prediction mode, selecting an execution manner of a triangular prediction unit mode according to a preset policy, determining motion information of the current block according to the execution manner of the triangular prediction unit mode, performing a motion compensation process based on the motion information, to obtain an inter prediction sample, obtaining an intra prediction sample according to the prediction mode of the current block, and combining the inter prediction sample and the intra prediction sample to obtain a prediction picture of the current block.