In this paper we analyze the most stable structure and the evolution of the reactivity of local using the indices of Fukui in systems phenolic substituted in position-para as amending function based on different methods. The results explain the substitutions: Electrophilic and aromatic nucleophilic and acylation in phenolic systems. The calculations were carried out at a level: HF/3-21G, B3LYP/3-21G, B3LYP/6-31G(d) and MP2/6-31+G(d), established the level of calculation for each type of reaction studied.