Python2 没有遇到同样的问题。
greg@greg-precise:~$ python3
Python 3.2.3 (default, May 3 2012, 15:51:42)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from gi.repository import Gtk
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named gi.repository
（为清晰起见添加了换行符）