It concerns many aspects of civil law systems, especially closely associated with such legal systems as acquisition with good-will, illegal profits, and title-defect warranty.

Change of the legal structure of sales contract,acquisition of title by good will and notification of jus in rem put liability incurred by defects of right into an embarrassing position.

The institution of the guarantee of flaws is one of the non-complete fulfillments in essence, however, it has the independent value in legal system and it is an institution that parallels to leistungst?rungsrecht in German Civil Law, even after the revolution of the German Debt Law.

Since CISG(United Nations Convention on Contracts for International Sale of Goods)has adopted a relinquished stance to avoid dealing with issues of contract effect,it leaves a tough problem as to determining the contract effect on the seller s violation of warranty against defects of title.

The system of warranty to the defects of title has been playing a unique value and role in the maintenance of the security for trade and protection of the interests of consumers.

Guarantee liability about blemish has 2000 years history from the Roman Law founded.

First,Chinese law about the stipulation of blemish guarantee is not determined the guarantee liability about blemish system like the German civil law,it only determines the blemish guarantee duty for seller and takes the blemish duty as inadequate implementation.