The Unity of God and Universe is the basis of Ibn-al Arabi and Spinoza's thought. Ibn-al Arabi explains it through a mystical approach; based on his theory of existential unity God is unique real existence and the universe is his light. Spinoza analysis the theory of substantial unity by a rational and philosophical approach; he believes that God is one substance and the universe is the modes which has arisen from his attributes. In order to outline the philosophical implications of Unitarianism, this paper reviews and analyzes the issues like God's attributes; the orders and levels of his being; and his global necessity, on the basis of unity of God and Universe