By　introducing　a　new　method　of　solution　preparation,　systems　of　equimolar　mixing　cationic/anionic　surfactants　with　dissymmetric　lengths　of　alkyl　tails　were　investigated　using　light　scattering,　rheology,　and　freezing-fracture　transmission　electron　microscopy　(FF-TEM)　measurements,　in　which　the　cation　was　docosyltrimethylammobium　bromide　(C22TABr)　and　the　anions　were　sodium　alkylcarboxylates　(Cn−1COONa,　n　=　4,　6,　8,　10,　12,　14,　16).　The　results　showed　that　spherical　micelles　were　favored　when　the　cationic/anionic　surfactants　had　highly　dissymmetric　length　tails　(C22/n4).　With　decreasing　dissymmetry　of　the　alkyl　tail　lengths,　the　aggregates　transformed　to　rod-like　micelles,　worm-like　micelles,　and　finally　vesicles.　In　the　vesicle-formed　cases,　the　size　of　the　aggregate　considerably　increased　with　decreasing　dissymmetry　of　the　alkyl　tail　lengths.　By　analyzing　the　mechanism　of　aggregation,　the　geometry　of　the　cation/anion　pair　is　thought　to　determine　the　morphology　and　the　transition　of　aggregates.　©　2015,　Editorial　office　of　Acta　Physico-Chimica　Sinica.