The law of unjustified enrichment deals with the economic transferring without legal justification,assuming its equal footing to the law of contract and the law of tort.

The third part deals with the difference between constructive trust and real right system, unjustified enrichment in civil law system,the conclusion is that constructive trust and unjustified enrichment have substantive similarity.

The infringement of debt that illegal profit forms on the civil law, is an illegal civil behavior.

Unapproved sublet makes up infringement of title of lessor, but the rents collected by lessee don,t make up illegal profit.

It is absolutely true that the theory of Real Right Act damages the seller `s interest and the fairness of trade by transforming the seller` s claim for ownership into claim for illegal profit.

On application principles of unjust enrichment;

Unjust Enrichment in Private International Law;

After bona fide third party establishes the free acquiring in good faith,the interests of the original owners should adopt a balanced system of unjust enrichmen

Some Issues of the Performance Unjust Enrichment;