Abstract: This paper takes A-share listed companies from 2008 to 2017 as the research sample to investigate the economic consequences of commercial credit reallocation in the supply side structural reform-whether it is “icing on the cake” for the strong enterprises or “timely help” for the weak enterprises.The results show that: on the whole, the reallocation of commercial credit mainly shows the effect of “timely help”, the commercial credit resources mainly flow from the strong enterprises to the weak ones, the weak ones are the biggest beneficiaries of the reallocation of commercial credit, and this effect is sustainable in the supply-side structural reform. At the micro level, commercial credit reallocation can correct the distortion of credit resources in initial allocation period, which shows that on the one hand, the outflow of commercial credit from the strong enterprises reduces the free cash flow, inhibits the generation of agency problems, and on the other hand, the weak enterprises use the inflow of commercial credit to ease the financing constraints.At the macro level, the reallocation of commercial credit promotes resources to flow from industries with low returns to industries with high returns. Further analysis shows that the executives of the weak enterprises seek the help of the strong enterprises by means of the informal system such as the identity of “red top businessman” and the constantly improving external environment.

Key words: Key words：commercial credit reallocation, supply- side structural reform, agency cost, financing constraint, resource allocation efficiency