Electronic effects include induction effect and conjugate effect, which are the most important theoretical basis in organic chemical reactions. This paper expounds the concept and essence of these two effects, and gives theoretical elaboration and examples based on the effects on addition reactions. In addition, the position selectivity of addition reaction between asymmetric olefin and asymmetric electrophile is also discussed, which is markov rule. The effects of organic chemical reactions on electrophilic addition can be analyzed by using electron effect, and the products of organic chemical reactions can be judged.