Abstract: With the rise of credit risk and the increasing demand for guarantee, the effectiveness of guarantee companies has attracted more attention. China's professional guarantee companies are divided into two categories: national companies and local companies. Because their own attributes, shareholders' background and customer quality are different, and their guarantee effectiveness is obviously different. To improve the guarantee effectiveness from the following aspects: the enhancement of guarantee company resources and guarantee strength, the choice of guarantee customers, the improvement of overall credit environment and regulatory system will help to reduce the bond default risk and enhance the security and effectiveness of the bond market.