When I change type of payment, I found the money in mine account is lost

What do you mean 'found the money in mine account is lost' ? Do you mean your account's balance ? Your credit card ?

If your credit card then each time that ad or change card details a small temporary store holding charge may be applied to check that the card details are correct and valid and that it's registered to exactly the same name and address as on your iTunes account - it should disappear off your account within a few days or so.

Store holding charge : http://support.apple.com/kb/HT3702