Redundant construction，which is a key problem urgently needing to be solved and which always has perplexed China's real economy activities in the process of China's economic development，presently，however，domestic policy-making departments and academic circles have much disambiguation on the understanding of redundant construction and are short of scientific system for the evaluation on the extent and rationality of redundant construction，furthermore，excess capacity and excessive competition are always appearing as a alternative concept of redundant construction. In a sense，redundant construction is a kind of economic phenomenon with Chinese characteristics and is a different concept from excess capacity and excessive competition，whose essence is administrative. The basic way for overcoming redundant construction is to deepen the reform and to perfect market system，i.e. institutional innovation should be used to change and restrict governmental behaviors in order to realize real separation of administration from enterprise management. It is not suitable to divide redundant construction into marketable redundant construction and administrative redundant construction. Redundant construction may coexist with investment insufficiency，not all redundant construction is not reasonable，and high-side redundant construction is not all reasonable. As a result，the rationality of redundant construction should not be simply evaluated by capacity exploitation rate and regional static comparative advantage but should be considered from long-term and dynamic angle.