A video decoding method comprising: receiving a bitstream including a current transformation unit split information indicating whether a current transformation unit of a current level k is split into transformation units of a lower level (k+1), the current transformation unit of the current level k being included in a current coding unit, where k is integer; determining a context index indicating a context model among a plurality of preset context models based on a size of the current transformation unit of the current level k to which the current transformation unit split information belongs; obtaining the current transformation unit split information by entropy decoding the bitstream based on the context model indicated by the determined context index; when the current transformation unit split information indicates a split of the current transformation unit of the current level k, splitting the current transformation unit of the current level k into transformation units of the lower level (k+1), wherein: an image is split into a plurality of maximum coding units according to information about the maximum size of the coding unit, a current maximum coding unit among the maximum coding units is hierarchically split into one or more coding units of a current depth, when a coding unit of the current depth among the one or more coding units of the current depth is no longer split into coding units of a lower depth, the coding unit of the current depth is split into one or more transformation units according to a transformation unit split information, wherein, when the transformation unit split information indicates a split for the transformation unit of the current level k, four transformation units of the lower level (k+1) are obtained by dividing a height and width of the transformation unit of the current level k by two, and when the transformation unit split information indicates a non-split for the transformation unit of the current level k, the transformation unit of the current level k is no longer split. receiving a bitstream including a current transformation unit split information indicating whether a current transformation unit of a current level k is split into transformation units of a lower level (k+1), the current transformation unit of the current level k being included in a current coding unit, where k is integer; determining a context index indicating a context model among a plurality of preset context models based on a size of the current transformation unit of the current level k to which the current transformation unit split information belongs; obtaining the current transformation unit split information by entropy decoding the bitstream based on the context model indicated by the determined context index; when the current transformation unit split information indicates a split of the current transformation unit of the current level k, splitting the current transformation unit of the current level k into transformation units of the lower level (k+1), wherein: an image is split into a plurality of maximum coding units according to information about the maximum size of the coding unit, a current maximum coding unit among the maximum coding units is hierarchically split into one or more coding units of a current depth, when a coding unit of the current depth among the one or more coding units of the current depth is no longer split into coding units of a lower depth, the coding unit of the current depth is split into one or more transformation units according to a transformation unit split information, wherein, when the transformation unit split information indicates a split for the transformation unit of the current level k, four transformation units of the lower level (k+1) are obtained by dividing a height and width of the transformation unit of the current level k by two, and when the transformation unit split information indicates a non-split for the transformation unit of the current level k, the transformation unit of the current level k is no longer split. an image is split into a plurality of maximum coding units according to information about the maximum size of the coding unit, a current maximum coding unit among the maximum coding units is hierarchically split into one or more coding units of a current depth, when a coding unit of the current depth among the one or more coding units of the current depth is no longer split into coding units of a lower depth, the coding unit of the current depth is split into one or more transformation units according to a transformation unit split information, wherein, when the transformation unit split information indicates a split for the transformation unit of the current level k, four transformation units of the lower level (k+1) are obtained by dividing a height and width of the transformation unit of the current level k by two, and when the transformation unit split information indicates a non-split for the transformation unit of the current level k, the transformation unit of the current level k is no longer split. wherein, when the transformation unit split information indicates a split for the transformation unit of the current level k, four transformation units of the lower level (k+1) are obtained by dividing a height and width of the transformation unit of the current level k by two, and when the transformation unit split information indicates a non-split for the transformation unit of the current level k, the transformation unit of the current level k is no longer split.