A method of decoding a video, the method comprising: receiving a bitstream of an encoded video; extracting, from the bitstream, information about a maximum size of a coding unit which is a data unit in which a picture is decoded, information about a maximum depth indicating a total number of possible times a maximum coding unit is split, and information about a coded depth and an encoding mode for coding units of the picture; splitting the picture into a plurality of maximum coding units using the information about the maximum size of the coding unit; and decoding the picture based on coding units of a hierarchical structure split from each maximum coding unit among the plurality of maximum coding units, using the information about a coded depth and an encoding mode, wherein: the information about a coded depth comprises split information indicating whether a coding unit of a current depth, among the coding units, is split into coding units of a lower depth, the encoding mode comprises information about a partition type of a coding unit of the coded depth among the coding units, and information about a prediction mode of the coding unit of the coded depth, the each maximum coding unit is hierarchically split into coding units of at least one depth according to the split information, a minimum coding unit among the coding units is determined by splitting the each maximum coding unit by the maximum depth, and the decoding the picture based on coding units comprises: when the split information indicates a split for the coding unit of a current depth, among the coding units of at least one depth, determining the coding units of a lower depth by dividing a height and width of the coding unit of a current depth by two, and when the split information indicates that the coding unit of a current depth is no longer split as the coding unit of the coded depth, determining at least one prediction unit obtained from the coding unit of the current depth by using the information about a partition type, performing prediction on the coding unit of the current depth based on the at least one prediction unit by using the information about a prediction mode, determining at least one transformation unit obtained from the coding unit of the current depth and performing inverse transformation on the coding unit of the current depth based on the at least one transformation unit. receiving a bitstream of an encoded video; extracting, from the bitstream, information about a maximum size of a coding unit which is a data unit in which a picture is decoded, information about a maximum depth indicating a total number of possible times a maximum coding unit is split, and information about a coded depth and an encoding mode for coding units of the picture; splitting the picture into a plurality of maximum coding units using the information about the maximum size of the coding unit; and decoding the picture based on coding units of a hierarchical structure split from each maximum coding unit among the plurality of maximum coding units, using the information about a coded depth and an encoding mode, the information about a coded depth comprises split information indicating whether a coding unit of a current depth, among the coding units, is split into coding units of a lower depth, the encoding mode comprises information about a partition type of a coding unit of the coded depth among the coding units, and information about a prediction mode of the coding unit of the coded depth, the each maximum coding unit is hierarchically split into coding units of at least one depth according to the split information, a minimum coding unit among the coding units is determined by splitting the each maximum coding unit by the maximum depth, and the decoding the picture based on coding units comprises: when the split information indicates a split for the coding unit of a current depth, among the coding units of at least one depth, determining the coding units of a lower depth by dividing a height and width of the coding unit of a current depth by two, and when the split information indicates that the coding unit of a current depth is no longer split as the coding unit of the coded depth, determining at least one prediction unit obtained from the coding unit of the current depth by using the information about a partition type, performing prediction on the coding unit of the current depth based on the at least one prediction unit by using the information about a prediction mode, determining at least one transformation unit obtained from the coding unit of the current depth and performing inverse transformation on the coding unit of the current depth based on the at least one transformation unit. when the split information indicates a split for the coding unit of a current depth, among the coding units of at least one depth, determining the coding units of a lower depth by dividing a height and width of the coding unit of a current depth by two, and when the split information indicates that the coding unit of a current depth is no longer split as the coding unit of the coded depth, determining at least one prediction unit obtained from the coding unit of the current depth by using the information about a partition type, performing prediction on the coding unit of the current depth based on the at least one prediction unit by using the information about a prediction mode, determining at least one transformation unit obtained from the coding unit of the current depth and performing inverse transformation on the coding unit of the current depth based on the at least one transformation unit.