A method of decoding an image, the method comprising: obtaining a square current coding unit hierarchically split from a maximum coding unit according to a current depth; obtaining one or more prediction units from the current coding unit by equally splitting a width or a height of the current coding unit by two, or by equally splitting both the height and the width of the current coding unit by two, or by determining the current coding unit as the one prediction unit; obtaining a prediction mode information of a current prediction unit in the current coding unit from bitstream; when a prediction mode of the current prediction unit is inter-prediction mode and a motion vector predictor of the current prediction unit is determined according to an explicit mode instead of an implicit mode, determining a plurality of motion vector predictor candidates from among motion vectors of previously decoded neighboring prediction units adjacent to the current prediction unit, wherein the explicit mode is a mode which determines the plurality of motion vector predictor candidates and determines the motion vector predictor of the current prediction unit based on a motion vector predictor information indicating the motion vector predictor of the current prediction unit among the plurality of motion vector predictor candidates, and the implicit mode is a mode which determines the motion vector predictor of the current prediction unit without using the motion vector predictor information; and determining a motion vector predictor of the current prediction unit from among the motion vector predictor candidates based on the motion vector predictor information obtained from the bitstream, wherein the previously decoded neighboring prediction unit comprises a first prediction unit that is located on a lower-left side of the current prediction unit, that is, directly below a lower-most prediction unit among left prediction units adjacent to a left side of the current prediction unit obtaining a square current coding unit hierarchically split from a maximum coding unit according to a current depth; obtaining one or more prediction units from the current coding unit by equally splitting a width or a height of the current coding unit by two, or by equally splitting both the height and the width of the current coding unit by two, or by determining the current coding unit as the one prediction unit; obtaining a prediction mode information of a current prediction unit in the current coding unit from bitstream; when a prediction mode of the current prediction unit is inter-prediction mode and a motion vector predictor of the current prediction unit is determined according to an explicit mode instead of an implicit mode, determining a plurality of motion vector predictor candidates from among motion vectors of previously decoded neighboring prediction units adjacent to the current prediction unit, wherein the explicit mode is a mode which determines the plurality of motion vector predictor candidates and determines the motion vector predictor of the current prediction unit based on a motion vector predictor information indicating the motion vector predictor of the current prediction unit among the plurality of motion vector predictor candidates, and the implicit mode is a mode which determines the motion vector predictor of the current prediction unit without using the motion vector predictor information; and determining a motion vector predictor of the current prediction unit from among the motion vector predictor candidates based on the motion vector predictor information obtained from the bitstream, wherein the previously decoded neighboring prediction unit comprises a first prediction unit that is located on a lower-left side of the current prediction unit, that is, directly below a lower-most prediction unit among left prediction units adjacent to a left side of the current prediction unit