Abstract: For a long time, the broker's disclosure duty in intermediary disputes has lacked a unified standard, and it has not been regulated in Civil Code. In the increasingly complex economic environment, this problem needs to be solved urgently. In this article, a number of cases were searched and selected in accordance with relevant theoretical perspective. It also analyzes the factors in the reference case that affected the limitation of truthful disclosure duty; on this basis, this article finally draws a conclusion to determine the extent and content of truthful disclosure duty, that is, all brokers should truthfully report the available facts that are relevant to the conclusion of the contract, and all brokers shall not intentionally conceal or misrepresent the facts, at the same time, all brokers shall pay reasonable attention to the authenticity of the reported facts. On this basis, the business brokers shall do due diligence and report all important facts related to the conclusion of the contract and the performance of the contract.