By interrupting the traditional approach to the distinctiveness of the order of knowledge and the order of nature (which was the procedure of many philosophers like Aristotle, and his scholastic disciples, more especially of Thomas Aquinas and even Descartes and Cartesian), and acquiring a unified science, Spinoza changes the customary order of philosophizing and begins his famous book, Ethics, with a treatise on God, nature or substance, a being that, is assumed, first by nature, i.e. in the order of nature, (...) but not first for us, i.e. in the order of knowledge. To accomplish this procedure, Spinoza, on the one hand attributes the extension to the God and on the other hand, chose the geometrical method that implies definitions, axioms and postulates that harmonize with his procedure, to expose his views. In this article, by analyzing Spinoza’s geometrical method, we try to show that how Spinoza achieved his methodological intentions. (shrink)