Oligomerization of light olefins produces gasoline or fuels. The kinetic network involves thousands of species and even more reactions. To develop a microkinetic model, the preliminary generation of a mechanism, as detailed as possible, is necessary. The classical single event network generation algorithm does not handle an exhaustive large oligomerization network. To be able to generate the network, qualitative a priori information on the kinetic rate scales are introduced. Principles of the new generation distinguish quasi-equilibrium reactions and rate determining steps ( from a generation point of view). Each type of reaction is generated step by step. During the generation step of the equilibrium reactions, every possible reaction of this kind, initiated from the already generated species, is created, building sets of species that are linked by one or several reactions. During the generation step of the rate determining step reactions, the new species are linked by only one new reaction. This algorithm was only applied for the generation of alkylation and a cracking reaction and allowed in a few steps the generation of approximately 80 000 species.