China's interbank bond market is an institutional investor market, and transactions are more information-based. Whether and how informed trading can affect credit bond pricing is an urgent problem to be solved in the study of China's bond asset pricing. This paper uses credit bond issuance and trading data and stock high-frequency trading data from May 2014 to December 2020 to construct informed trading probability and bond liquidity indicators. Using regression analysis and adjustment and mediation effect test methods, this paper studies the impact of informed trading on China's interbank credit bond pricing and the channel role of liquidity. The results show that the probability of informed trading has a significant positive impact on credit bond spreads. Informed trading leads to an increase in credit bond spreads by amplifying bond illiquidity. The amplifying effect of informed trading on credit bond spreads is stronger for bonds with high illiquidity. The amplifying effect of informed trading on credit bond spreads will be stronger in private enterprises, enterprises with low information transparency, and high debt ratios. This study reveals the risk nature of informed trading in China's interbank bond market, which helps to deepen the understanding and management of the bond market.