The principle of change of circumstances is the important principle of debt law that make the honest&credit principle as the starting point.

Once China began to work out a uniform contract law in the 90s of last century, the principle of change of circumstances was drawn some attention.

The system of changed circumstances is a kind of doctrine governing the performance of the contract.

As an important principle in the performance of contract, the principle of the changed circumstance is provided minutely in civil law countries and common law countries.

Principle of changed circumstance(clausal rebus sic stantibus) is referred as after the contract is established and before it finishes the implementation, the objective factors which is basic to the contract have fundamental changes that are not caused by one or two parties, with the result of very difficult implementation of the contract.

Analyze the Principle of Change of Circumstances and Its Application in the Judicial Practice of China;

This article mainly analyses and compares two important concepts in the contract implementation,which are force majeure and frustration of purpose,which hopes to help us to apply and hold them exactly and comprehensively in the practice of the contract law.

The principle of frustration of purpose is the important principle of contract performance,its character stressing practical rationality has been provided in detail in both coutries of continent law system and countries of Ocean law system.

China is drafting its own civil code, which is the opportunity of building up the rules of rebus sic stantibus after the issuing of Contract Law.

Rebus sic stantibus system developed from case to statute law has become the current of world civil lawmaking .

If rebus sic stantibus principle is provided for in the law of the land contract in rural areas,it will play a crucial role in solving these dissensions,promoting agricultural development and maintaining rural stability.