The present application relates to the technical field of video coding, and especially relates to a coding unit division fast decision method and
system based on multi-functional video coding, comprising constructing a
quadtree division prediction network, using the network to judge whether a
coding tree unit needs to perform
quadtree division, and obtaining a coding unit after performing the
quadtree division; constructing a mixed tree division prediction network, using the network to judge whether the coding unit needs to be divided, stopping division if the coding unit does not need to be divided, otherwise judging whether the coding unit adopts
binary tree division or
ternary tree division, and taking a smaller coding unit division prediction value in parallel branches as a final prediction result. The present application improves coding efficiency, and can balance the relationship between visual quality and coding efficiency by selecting different threshold values according to specific scene needs.