The invention relates to a tree structure operation method and system used for a cloud computing environment. The tree structure operation method and system used for the cloud computing environment comprises the following steps of establishing a node relationship table according to node information of nodes in a tree structure, wherein the node relationship table comprises node identifiers and a node-father node sequence, and the node-father node sequence records the nodes and a father node of the nodes; obtaining a target node identifier subjected to operation, searching for the node-father node sequence in the node relationship table according to the target node identifier, and updating the node-father node sequence according to contents of the operation; and modifying the tree structure according to the updated node-father node sequence. According to the tree structure operation method and system used for the cloud computing environment, a recursive query of the nodes does not need to be carried out and relatively high operation efficiency is achieved.