The Mechanism of Autocatalitytic Reactions divided into four chapters: autocatalytic reactions in homogeneous systems, autocatalysis, oscillations and chemical instabilities and continuous mixing reactor (perfect). The chapter 1 presents the fundamental concepts related to autocatalytic reactions of the order one, two and three but autocatalytic reactions kinds of order the one, two and three. The chapter 2 is divided into four chapters and includes basic concepts related to the autocatalysis, autocatalysis direct, indirect and inhibition. The chapter 3 Oscillations and Chemical Instabilities includes all models found in the literature characterizing oscillating reactions: modelul Lotka, modelul Lotka-Volterra, model Alternator, model Explodator, model with Four Intermediates, model with Dimmer, model Brusselator, model Oregonator, model Berlinator and model Braylator, and subsections related to the study of second order autocatalytic reactions in reactors and closed three consecutive first order reactions. The chapter 4 includes four chapters related to the continuous reactor with perfect mixing and behavior autocatalytic reactions in the reactor.