This application provides a garbage data scrubbing method and a device, and relates to the field of terminals, to resolve a problem that delivering a discard message in a file system transaction affects a user foreground operation. The method includes: obtaining an IO busy/idle status of a terminal at a current moment, where the IO busy/idle status includes a busy state and an idle state (S301); and if the IO busy/idle status of the terminal at the current moment is the idle state, delivering a discard message to a storage device (S302), where the discard message includes an initial address and a size of to-be-scrubbed physical space in the storage device, and the discard message is used to unbind a mapping relationship between a physical address of the to-be-scrubbed physical space and a corresponding logical address.