If internal interactions exist in isolated systems, entropy decrease will be possible. From this we discuss management as a typical mode, which includes much internal adjustment and control, and through them to achieve more ordered, more efficient, competitive, and can better survive and develop. A key of management is to change the natural tendency disorganized with entropy increase, and build the best system with entropy decrease. It is the thermodynamic meaning of management. Further, this theoretical mode may be extended to ecology, biology, and sociology, etc. The naturally formed and artificially intervened ecosystems are all through interaction and regulation within the systems to reach the dynamic balance, order and entropy decrease. These systems have all some constant evolutions, and reach optimization processes with order and entropy decrease. In a word, much social systems and human society are dominated by non-equilibrium dynamic processes, which are accompanied often by order and entropy decrease.