http://docs.xfce.org/faq or http://docs.xfce.org/apps/terminal/start which opens when you press F1.

Thank you very much.

I use

A number of Xfce applications (Xfce Terminal and Thunar for 
example) support the standard GTK+ way of changing 
shortcuts: simply hover over the menu option with the 
mouse pointer and press the keyboard shortcut you want
 to rebind it to. 

to solve the problem.

i love xfce4-terminal  and have used for 5years, because i could customize almost everything, like fonts, background, colors.......

however, after the new update, i found a problem that i cannot define the shortcut. in the old version, there was a "Shortcuts" option in Preferences, but it seems there is no such one in the new version.  what does it mean? ain't i allowed define my own shortcuts or i should  do it in some files?

thanks and best wishes