A method for deriving motion information for a current block includes: determining whether the current block and a top neighboring block of the current block are in a same coding tree unit (CTU) or not; obtaining a position of a spatial motion information candidate for the current block; obtaining motion information corresponding to the position of the spatial motion information candidate, depending on the result of whether the current block and top neighboring block of the current block are in the same CTU; adding the obtained motion information to a motion information candidate list for the current block; obtaining a value of a first index of a motion information candidate; and deriving motion information of the current block based on the motion information candidate list and the value of the first index.