I tried to synchronise my Thunderbird address book with GMail manually. So, I need to export the contacts into CSV format. However, there is encoding problem after exporting to CSV, because my contacts contian Chinese characters. The text file has encoding error if viewed by Gedit. I tried to import it from GMail, these errors still exist.
To solve it, I use the command-line to run Thunderbird with:
env LANG=en_US.utf8 thunderbird
This solves the problem after I tried to export the contacts to CSV format again. Actually, the Arch Linux is already set the locale (in /etc/rc.conf) as en_US.UTF-8.