The principles of legality, fairness, equality, voluntariness, unanimity through consultation, honesty and credibility shall be followed when concluding a contract or changing its contents.

1, the contract law is a law to adjust the trading relationship between equal subjects, which mainly regulates the conclusion, effectiveness, performance, alteration, transfer, termination, liability for breach of contract and various famous contracts. In our country, contract law is not an independent legal department, but an important part of our civil law.

2. Contract law is of great significance for regulating economic transaction relations, protecting the legitimate rights and interests of contract parties and maintaining normal transaction order. A good contract law can promote a country's economic development.