As an important problem in the system of performance of contract,the principle of performance of contract has some divergences theoretically and needs further study.

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.

As a rule, a contract will come through the whole course of talking over, sketching out, signing, performance, alternation, termination and coming to an end.

The employers should perform the obligation voluntarily,and the workers can call on the employers through application.

From the laws and regulations of informing obligation of life insurance,the performing time,content,method and remission of informing obligation were analyzed,and its influence on life insurance contracts was further discussed.

So it is necessary for us to discuss the worthiness of establishing the notification system in assignment contract and the fulfilling subject,time and manner of the notification duty for purpose of carrying assi.

Donation subject to collateral also has some special rules during fulfillment.

The Contract Law of People s Republic of china stipulates conventional dealings in daily life by means of legislation so as to fulfil any contract properly.