Augustine is usually understood as the origin of Christian patriarchy and debasing woman. The major feminist criticism is that Augustine does not give woman the "image of God" (Imago Dei) as man equally. The Trinity Book 12 mainly concerned about the Imago Dei of woman. This article is a study of this text, focusing on this concept. By reviewing the background, purpose and illustration of Augustine on woman's Imago Dei, this article shows the original shape of Augustine's thought, including its strengths and weaknesses. On this basis, this article re-evaluates the value of woman's Imago Dei and responds to the feminist critics.