This tutorial is written based on our Bank of China experiences. Other banks may be different (but generally similar).

What to do When Your Card is Lost or Stolen

1] When you have lost your card, go to the bank branch office where you got your card.

2] Get a ticket by selecting "Personal Banking"

3] Tell the people at the front desk that you lost your card.
If they dont speak English, you can say this, or write this on paper and give it to them:

(Chinese)

(pin yin)"Wo de ka diu le"

4] They will give you a form, which is seemingly unavailable in English. This form and the form that you would use if you lost your passbook are the same.
(Form: "Application Form for the Loss of Deposit Certificate")[image of form]

5] Fill in the form.

6] If you want to get a new card (to replace your old and/or lost card) you will need to fill in another form. This form is not available in English.
(Form:  this means "new card application form")

7] Wait for your number to be called.

8] When your number is called, go to the the window that is announced (or shown on the screen).

9] At the window, give the bank teller the form that you have completed, and your passport. The teller will begin to process the form.

10] The teller will inform you that you can return after 7 days to retrieve your new card at the same branch office.

Tip
If you have lost your card, you can call the bank, or go to any branch to report it lost. You must then fill out a lost card form at the bank where you got your card (see step 4) within 5 days.

11] The fee for having a lost card replaced is 15 RMB.

In our experience

Replacing the card
Sometimes the card's magnetic strip looses its magnetic field, in this case you will need to replace it, you may or may not have to pay the replacement fee, depending on the damage.

Lost cards
If you loose your card remain calm. First: if the ATM ate it (it ate mine), talk to the bank that runs the ATM before you cancel your card. They might have a number on the ATM you can call, or you can go to a branch office. If you don't know how or where you lost it, you definately need to have the bank turn off the card temporarily, then you go look for it. If someone took it, they probably can't do anything with it unless they have your PIN, just keep looking, then when you give up (after a few days) cancel the card.