This paper seeks to light up the relationship between Dialectic and Demonstration in Ibn Rushd's philosophy. this research examines two "ideological" statements at least by some contemporary scholars—statement which require a critical review of the concept of Dialectic and its functions. On one hand, this is manifested inn his defense of discourse dialectic; on the other, in a disdain for Dialectic, because it is against the principles of Demonstration.These two theses Which did not understand the texts of Ibn Rushd,who defends both Dialectic and Demonstration. For the philosopher of Cordoba, the Dialectic is not generally negative; it has many benefits in theoretical sciences, civil policy and its main role in the first philosophy.