On Changed Circumstance Principle

The aim of this thesis is questing the rationality and feasibility of legitimate Changed Circumstance principle by the analysis of it and its application.Afterwards advance some new views of my own in the issue.This thesis can be divided into six parts.In the first part I introduce the concept and the development of Changed Circumstance principle from"clausula rebus sic stantibus"of Roman law to modern law and from Common Law countries to Civil law countries,finally faces the attitude of our legislator in the issue of legitimate Changed Circumstance principle.This part has an effect on historical proof.In the second part I vindicate the rationality of legitimate Changed Circumstance principle from three aspects which are theory, background and judicial actualities.In the third part I introduce the contents of Changed Circumstance principle, including the conditions of application,the procedure of application and the effect of application.In the fourth part I make some differences between Changed Circumstance principle and any other similar legal systems,such as frustration of contract in Common Law countries,force majeure and unconcsionability in our contract law.This part draws a clear distinction between the effect of these system in contract law.In the fifth part I analyze two serious questions about the application of Changed Circumstance principle in judgement,which are the freedom rights in trial of a judge and the differences between commercial risk and Changed Circumstance principle.In the conclusion of the thesis I summarize the experiences of legitimate Changed Circumstance principle in ninety 20 century,then try to devise the articles in the basic of Civil Code.