Finally,I solved the problem because I put rf24 library before u8glib.
But I found your library use too much program memory.How can I reduce the memory usage.I saw compilation detail.It compile other screen's c files.
U8glib contains a lot of files, but only code which is really used goes to PROGMEM area. In general, i would say that it should be comparable with the adafruit library.
Second answer is: There is a huge impact of the fonts that you use.
Have a look here:http://code.google.com/p/u8glib/wiki/fontgroupx11#5x7
Compare u8g_font_5x7 and u8g_font_5x7r. u8g_font_5x7 will use 1624 bytes (as you can see on the web page) but it will contain some none ANSI chars like german umlaut äÄ öÖ üÜ. If you do not need such chars, you can use u8g_font_5x7r which only requires 789 bytes. You can optimize your code size by selecting a suitable font.