Abstract: I have provides for the implementation of the contract system. System is the fulfillment of the contract bond to achieve the prerequisite for social credit is the foundation of all other contract is the destination of the legal system. System for the implementation of the contract include: contract performance in principle, the contract performance in the right defense, preservation of the contract system. In addition, contractual obligations, including the identification, the third person to participate in the contract to perform as well as changes in the contract provisions. Article main principles of contract performance, the right to defense, the preservation of the contract the meaning, importance should be done to explain the problem, other issues were briefly reviewed.合同履行Contract performance 合同履行原则The principle of contract performance 合同履行中的抗辩权Contract performance in the right defenses 合同保全Contract preservation