Based on the data of China's A-share listed companies from 2008 to 2018, we examine the impact of guarantee network on analysts' earnings forecast bias. We find that the companies in the guarantee network will significantly increase analysts' earnings forecast bias and reduce forecast accuracy. Further analyses suggest that the effect of guarantee network on analysts' earnings forecast bias is more significant for firms are two-way guarantee, in trans-provincial financing guarantee circles, in the guarantee network for a long time and in the structural hole position of guarantee network. However, this negative impact will be mitigated, even disappear, if the companies in the guarantee network choose to exit the network. Further analyses find that accounting information comparability is the channel through which guarantee network affects analysts' earnings forecast bias. In addition, we also find that the internal governance mechanisms of high-quality internal control, good corporate governance, as well as external governance mechanisms such as media supervision and institutional investor governance, can effectively reduce the negative impact of guarantee network on analysts' earnings forecast bias. Our study enriches the research on the impact of the guarantee network on the information environment of the capital market from the perspective of analysts' earnings forecast, helps to further sort out the impact of complex relationships between enterprises on the efficiency of information transmission in the capital market, and effectively alleviate the guarantee network for all participants in the capital market. Negative impacts provide empirical evidence and policy direction.