Abstract: The implementation of the State Council′s Opinions on Strengthening Local Government Debt Management and the new budget law aims to clarify the relationship between local governments and local financing platforms, ease the implicit guarantee of local governments on urban investment bonds, and promote the market-oriented issuance of urban investment bonds.In order to test the implementation effect of policies and regulations, this paper uses the data of urban investment bond issuance in 2009-2017 as the research sample, and uses the double difference method to study the difference of the impact of guarantee measures on the credit spread of urban investment bond issuance before and after the implementation of No.43 document and the new budget law.The results show that: after the implementation of the policies and regulations, the guarantee measures can significantly reduce the credit spread of urban investment bonds, and the effect of the guarantee measures to reduce the credit spread of urban investment bonds is better in the areas with better financial situation of local governments, and the implementation effect of the policies and regulations is sustainable.It shows that No.43 document and the new budget law can effectively clarify the relationship between local governments and local financing platforms, and weaken the implicit guarantee of local governments to urban investment bonds.The market-oriented transformation of local financing platform is a step-by-step process. We should focus on the local financing platform with poor financial status of the government and improve its operation level and profitability.

Key words: local financing platform, urban investment bond, guarantee measures, implicit guarantee