here is the art.gnome.org's how-to:
Extract your Nautilus theme (tar zxf theme_name) then in a Nautilus window, goto "Preferences" and click on "Edit preferences...". In the window that appears, click on "Appearance" in the list on the left hand side of the window. Click the "Add New Theme..." button and select the directory where the theme you just extracted placed itself. This copies the theme to ~/.nautilus/themes so you can now delete the extracted files/directories. Your new theme should now appear in the "Nautilus Themes" list (above the "Add New Theme..." button).
yeah, I see the Edit-->Preference,but wher is the "Edit preferences..."? no where...