Abstract: A method of belief contraction based on the forgetting theory is presented for the information loss after belief contraction under the framework of the classic belief theory. At first, this method is proved theoretically to be able to meet the assumption of the AGM theory. Then through examples, it is illustrated that the belief contraction based on the forgetting theory expressed by the firstorder predicate can save more old information and obey the minimal change principle.

Key words: belief revision;belief contraction;forgetting theory