Investor protection mechanism is a main component of the capital market system. In mature foreign capital markets，there have been quite established investor protection mechanism thanks to the rapid updates of economics theories，continual expansion of the securities market and incidents of investor interest being jeopardized. Their main strategy is to provide risk warning through information disclosure and put in place risk-sharing measures. Typical systematic measures include bond trustee management system，bond guarantee system，information disclosure system，bond credit rating，investor protection funds，and bond insurance. China has also established some bond investor protection arrangements，which largely cover the above-mentioned aspects. However，there is still much room left for China to improve the system in terms of establishment and implementation of concrete systematic measures. As the bond market expands continually，the types of issuing entities have diversified and the credit risks have become more complicated，improving the investor protection mechanism has become an important component of the market systematic build-up. The following measures should be taken to improve the investor protection system. First，the legal framework of the securities market should be improved. Second，the corporate governance structure should be improved. Third，investment education should be strengthened. Last but not least，the credibility awareness should be enhanced.