Abstract: The decline in the effectiveness of monetary policy is a typical fact of China's macroeconomic policies in recent years, so exploring the underlying reasons and optimization measures has become an important topic in the theoretical and practical circles. For this reason, based on the perspective of the changes in the distribution channels of monetary base, this paper first conducts a theoretical analysis, and then demonstrates at multiple levels how the changes in the distribution channels of monetary base affect the effectiveness of China's monetary policy through macroeconomic effect analysis and micro-mechanism testing. The research reaches the following conclusions. First, according to the estimation results of the VAR model with time-varying parameters, the macroeconomic effects of different channels of monetary base are quite different, but no obvious time-varying characteristics have been found, so one of the important reasons for the decline in the effectiveness of China's monetary policy is the structural changes of distribution channels of monetary base. Second, in terms of micro-mechanisms, there are big differences in the effects of different distribution channels of monetary base on corporate investment, which is an important channel for the distribution of monetary base to affect the effectiveness of monetary policy. Third, there are significant differences in the ability of different distribution channels of monetary base to ease corporate financing constraints. Based on this, this paper puts forward constructive suggestions for optimizing the effectiveness of China's monetary policy.

Key words: distribution channels of monetary base, the effectiveness of monetary policy, corporate investment, financing constraints