Provided is a multi-layer video decoding method. The multi-layer video decoding method includes: obtaining, from a bitstream, dependency information indicating whether a first layer refers to a second layer; if the dependency information indicates that the first layer refers to the second layer, obtaining a reference picture set of the first layer, based on whether type information of the first layer and type information of the second layer are equal to each other; and decoding encoded data of a current image included in the first layer, based on the reference picture set.