According to the Chinese immigration law, if your visa has been
expired less than 10 days, it's not necessary to pay any fine. You
should go to the immigration office, where the officer will ask
some questions and make a record of your statement. The officer
will also tell you not to let your visa expire again.
If your visa has been expired more than 10 days, they will
charge you a fine. The fine is 500 yuan per day except the first 10
days, and the maximum is 5,000 yuan. For example, if you overstay
12 days, they will charge (12-10)*500=1000 yuan.
This is the contact information for the immigration office; you
can go there when your visa expires:
Address: No. 1500 Min Shen Rd. , PuDong, Shanghai, China.
Telephone: 021-2895 1900
(China.org.cn March 16, 2007)