Here we reported that the Large-billed Crow (Corvus macrorhynchos) could open the next-boxes and predate the eggs, nestlings or adults of Green-backed Tit (Parus monticolus). Totally 43 nest-boxes were found to be opened, of which 4 were recorded by cameras, 2 were witnessed by observers of being opened by the crows, and 20 were found crow activities nearby. We assumed that all the nest-boxes were opened by crows, as no human activities or other Corvids were found around the nest-boxes. Of these 43 nest-boxes been opened, 19 were at incubating and nestling period of the Green-backed Tit, and 5 nest-boxes of adults, 3 nest-boxes of adults and eggs, 1 nest-boxes of adults and nestlings, 2 nest-boxes of nestlings and 8 nest-boxes of eggs were predated. For the cases that adults were predated, their blood and residual plumages could be detected. We suspect that crows might be able to open the nest-boxes by observing and learning from human practices, which would be confirmed by further studies.