The practice of China's economy proves that supply of monetary reflects loose degree of general social demand, which prevents inflation effectively. While in deflation, loose degree of general social demand is lack of sensitivity, then it cannot be treated as the media aim any more. As of the none-symmetrical quality of monetary policy, the Central Bank is required to choose the different leading index of different periods as the media aims. After analyzing the pros and cons given by domestic scholars, the essay points out that, in time of deflation, the Central Bank can treat the ratio between storage of products and general sum of consumption as the media aim of monetary policy.