The invention discloses a method for securing transactions for electronic deposits. In the method, a grey lock mark is merged into an electronic deposit of an IC card and becomes one of electronic deposit attribute parameters. When locking the IC card, i.e. setting a grey lock mark on the IC card, a locking card source is recorded on the IC card at the same time. When debiting, judging the locking card source and combining the debiting operation with the unlocking operation into a one step operation, i. e. after debiting successfully, unlocking is automatically done. This can solve illegal unlocking problems effectively and thoroughly, so electronic deposit consumption transactions are more secure and convenient.