Abstract: Public organization system is a complex adaptive system by nature，which is driven forward by the games played by interest groups.The complex adaptive system theory reveals that interest game in public organization system mainly takes the form of cooperative competition.This results mostly from any single interest group′s bounded rationality，uncertainty，and being minority in decision making process.Cooperative competition can help avoid opportunism，improve rationality，contribute to form majority，and reduce uncertainty through bureaucracy in competition.Deconstruction and integration of the value creating process is the most important procedure in interest group games and also the cause of such games.

Key words: complex adaptive system, public organization system, interest groups, value chain, game