An interlayer video decoding method comprises reconstructing a first layer image based on encoding information acquired from a first layer bitstream; reconstructing a second layer current block determined as a predetermined partition mode and a prediction mode by using interlayer prediction information acquired from a second layer bitstream and a first layer reference block corresponding to a current block of a first layer reconstruction image that is to be reconstructed in a second layer; determining whether to perform luminance compensation on the second layer current block in a partition mode in which the second layer current block is not split; and compensating for luminance of the second layer current block according to whether luminance compensation is performed and reconstructing a second layer image including the second layer current block of which luminance is compensated for.