A video frame fade-in/fade-out detection method is provided, the detection method includes: before motion search, performing inter-frame comparison on block direct current components in some rows of a picture or performing inter-frame comparison on block direct current components in a partial area of a picture; collecting statistics on an inter-frame comparison result; determining whether fade-in/fade-out exists, to choose whether prediction is in a weighted mode; and if it is detected, by means of inter-frame comparison on block direct current components on some rows, that no global fade-in/fade-out exists, selecting a partial area within a range of some detected rows to perform inter-frame comparison on block direct current components again, and detecting local fade-in/fade-out. In the present invention, fade-in/fade-out is detected under the premise that easy hardware implementation is ensured, which saves a bandwidth and improves block match accuracy; in addition, the present invention proposes a solution for local fade-in/fade-out.