1. A system for generating a tree map for tree map visualization, the system comprising: a node information obtaining module, implemented by a processing device, and configured to obtain node information of a plurality of nodes to be processed, the plurality of nodes to be processed being all sub-nodes sharing a same parent node and the node information comprising at least sizes of the nodes; a candidate node determining module, implemented by the processing device, and configured to determine from the plurality of nodes a plurality of candidate nodes whose sizes are less than a threshold size; a super node determining module, implemented by the processing device, and configured to determine a super node including the plurality of candidate nodes based on the node information of the determined plurality of candidate nodes, a screen size, and the threshold size, such that when displaying in a zooming-in mode the super node on the screen, all candidate nodes in the super node are displayed at display sizes not less than the threshold size, wherein the super node determining module comprises: a module configured to rank the candidate nodes based on the node sizes of the candidate nodes; a module configured to divide the ranked candidate nodes into a plurality of candidate node subsets, a module configured to judge whether all nodes of each candidate node subset can be identified by zooming-in one time, and divide unqualified candidate node subsets until all nodes of all candidate node subsets can be identified by zooming-in one time; and a module configured to determine the super node based on the divided candidate node subsets; and a display module, configured to determine data required for displaying the tree map based on the determined super node.