from wikipedia:
Babylon is an important Rastafarian term, referring to human government and institutions that are seen as in rebellion against the rule of JAH (God), beginning with the Tower of Babel.
It is further used by some to mean specifically the 'polytricksters' who have been oppressing the black race for centuries through economic and physical slavery.
Rastafari is defiance of Babylon, sometimes also called Rome — in part because of the 1935 Italian invasion of Ethiopia, then ruled by Rastafari's 'Living God,' Haile Selassie I, and partly because as the head of the Roman Catholic church the Pope is considered an opponent of Selassie I and Rastafari.
Babylon the Great and Whore of Babylon are apocalyptic terms from the book of Revelation that may have been used to describe the pagan Roman Empire, which often persecuted Christianity.
Babylon is also sometimes used by some Rastas with the more specific meaning of "police", insofar as they are seen as executive agents of Babylon's will.