Ionogels have aroused wide interests in the field of flexible electronics. The combination of solid-state networks and ionic liquids opens up thousands of possibilities for ionogels. The unique structures of ionogels endow them excellent mechanical properties, conductivity and thermal stability to approach the challenge of flexible electronic. A large number of new ionogels have been developed by different methods including the exchange of solution, polymeric ionic liquid and in-situ reactions in ionic liquids (gelation of low molecular weight gelators, self-assembly of block polymers, formation of double-network structure, ionogel nanocomposites and direct polymerization of polymerizable monomers). The aim of this review is to discuss different preparation methods of ionogels and the comparison of their advantages.