Traditionally, we think Augustine as a typical Christian theologist. And we identify Augustine's libido as a shameful sin, which has a powerful drive to pull the human body away from the control of the will and to compel human beings committing crimes. Libido has a new meaning since Freud's theory of psychoanalysis, so we need to turn back to Augustine to refigure out what is libido in his term, and what is its relationships to the human will as well as to the feeling of shame. Now Foucault offers an untraditional understanding on Augustinian libido in his History of Sexuality volume 4, Les aveux de la chaire. Foucault argues that libido is not as traditionally think, as is outside the will, but rather is exactly in the will, and the process of feeling shameful of libido is a moral process by which the subject uses as the legalized justification to make defense of himself. He also discovers that Augustine's attitudes towards sexual desire and sexual activities are quite ambivalent, and this is the key to understand the process of moralization of sexuality in Western societies.