中小企业为我国经济社会发展做出了突出贡献,但却长期面临融资难题。为评估货币政策破解中小企业融资难题的效果,本文构建包含异质性企业的DSGE模型,创新性地将总量货币政策和结构性货币政策纳入统一的政策调控框架。结果发现：总量货币政策与结构性货币政策均能刺激经济,降息使通货膨胀大幅提升,降准释放的资金多数流入大型企业;但以定向降准和再贷款为例的结构性货币政策可以精准引导商业银行定向增加中小企业信贷投放,缓解中小企业的融资困境。“总量货币政策+ 结构性货币政策”通过稳住中小企业,平抑了供给冲击和需求冲击对宏观经济造成的波动,增强了经济稳定性,提高了社会福利。本文研究表明,短期可以通过货币政策协调补齐资源配置短板,长期必须深化改革建立市场化的金融体制,才能从根本上解决我国中小企业融资难题,实现经济高质量发展。

Since the adoption of the“reform and opening-up”policy, the private economy with small and medium-sized enterprises（SMEs） has achieved great development. It has played an important role in stabilizing growth, promoting innovation, increasing employment and improving people's livelihood. It is also an important force driving China's economic and social devel-opment. However, due to the preferences of financial institutions and favorable policies towards state-owned enterprises, SMEs are suffering from financing disadvantage in credit market and facing the dilemma of financing difficulties and financing expense.
In the dynamic stochastic general equilibrium （DSGE） model which includes heterogeneous enterprises, this paper incorporates aggregate monetary policy and structural monetary policy into a unified monetary policy framework, quantitatively analyzes the short-term and long-term effects of two types of monetary policies, and evaluates the effects of monetary policies on solving the financing problems of SMEs as well as the impacts on macro-economic stability.
The results shows that both aggregate monetary policy and structural monetary policy can stimulate the economy. From the short-term perspective,decreasing interest rate will lead to a sharp rise in inflation and the funds released by lower required reserve ratios will flow to large enterprises. The structural monetary policy, with the example of targeted cuts of required reserve ratios and re-lending,can guide the orderly flow of funds to SMEs and ease the financing difficulties of SMEs. From the long-term perspective, when the economy suffers from supply and demand shocks, structural monetary policy can coordinate with aggregate monetary poli-cy to increase the credit ratio of SMEs, reduce economic fluctuations, and thus improving economic stability and social welfare.
This paper suggests that efforts should be made to coordinate different types of monetary policies to improve resource allocation efficiency in short run, and deepen economic reforms to establish a market-oriented financial system in the long run, with the aim to finally resolving the financing problems of SMEs in China and achieve higher quality economic development.