This paper applies the Entropy weight method measure the efficiency of energy-saving and emission reduction during 1995-2010 at first. Designs the potential influencing factors of the energy-saving and emission reduction efficiency based on the theory of governmental regulation,and then identify the key factors that affect the efficiency of energy saving and emission reduction .With the result showing that per capita GDP and the number of environmental agencies and the number of environmental cases remarkable possess important correlation with the efficiency of energy saving and emission reduction.