Bond financing is an important form of enterprise financing, especially in the current direct financing is not smooth environment, whether the success and low cost of bond financing is related to the enterprise can survive in the economic "winter". In the process of bond underwriting, the bond underwriter is always in the position of information transmission, while the reputation of the underwriter plays a role of proving the efficiency of information transmission, and the information transmitted by the underwriter with higher reputation is generally considered to be more effective. Underwriter's reputation is likely to be an important factor affecting bond issuance cost. Taking corporate bonds from 2015 to 2021 as a sample, this paper studies the influence of underwriter's reputation on bond issuance cost. The study finds that the higher the underwriter's reputation is, the lower the bond issuance cost will be. And in a market with high liquidity, the effect of underwriter's reputation on reducing bond issuance cost will be enhanced. In the robustness test, the validity of the results in this paper was verified by changing the measurement method of underwriter reputation and Bootstrap test. This paper systematically analyzes the role of underwriter's reputation in the bond market and the way of influence, and provides an innovative perspective for studying the role of underwriter's reputation.