The applicant’s urban waste treatment PPP project selects operators through public bidding. In the bidding stage of the project，the applicant’s bidding documents on the standards and calculations of garbage disposal fees were different from those in common bidding documents，but the respondent did not raise any objections to this and did not ask for clarification. After the contract was signed，both parties adopted a vague attitude towards the payment of garbage disposal fees during the performance process，that is，the respondent applied for the payment according to his own understanding，and the applicant did not carefully check it，and immediately paid. Both parties also made changes to the contract’s payment standards and calculations in an informal way，but they were inconsistent with the contract，but the two parties continued to perform without disputes. During an audit conducted by the city Audit Bureau it was discovered that the two parties did not perform the contract in accordance with the contract and violated the law and requested correction. This resulted in disputes between the two parties. The disputes between the two parties are mainly in two aspects. In terms of procedures，the two parties first resolve the matter through an expert committee，but the two parties have inconsistent understandings of the composition of experts，their suggestions，and the nature of expert suggestions. On the issue of arbitration，the meanings of some clauses agreed by the two parties are unclear and contradictory. On substantive issues，the two parties have inconsistent understandings of the bidding documents and contract payment calculation standards；on the interpretation of the contradiction between the contract agreement and the industry standard There are also major disagreements；in the implementation，there are also major disagreements on the validity of contract changes.