This work consists of an analysis of the thought of Spinoza and intends to demonstrate the relations between metaphysics, ethics, politics and law in the spinozian reflections. The object of this thesis refers to the identification of the metaphysical and ethical structures of Spinoza´s works and aims at the exposition of the necessary link between these structures and the political and juridical concepts whose foundations are metaphysical and ethical. It is important to figure out that this thesis selects the ontological and ethical aspects of Spinoza´s works that are able to rebuild some political and juridical notions that had been insistently reaffirmed by the legal reasoning. The jurisprudence produced a solid consensus of the themes that involves the transcendent foundations of law, the constitution of law by a free and rational decision, the legitimacy of the state of exception and the opposition between ought and be. In the end, the thesis is oriented by the exposition of the spinozian concepts which are able to redefine the terms that sustain these consensual notions and to establish an alternative horizon to a better comprehension of these problems.