The present disclosure provides an encoding/decoding method using a tree structure. The encoding method for encoding image information includes: grouping predetermined areas having the image information into a plurality of groups, and generating a node value of each layer up to an uppermost layer by determining a minimum value or a maximum value of information to be encoded within grouped areas as information on the grouped areas; and encoding a difference value between the node value of each layer and a node value of an upper layer or a difference value between the node value of each layer and a value determined based on a preset criterion. Accordingly, the encoding efficiency and in turn the video compression efficiency are improved by using the tree structure in the encoding of various pieces of image information and the decoding of the resultant encoded data.