Nanostructural　electroconductive　poly(aniline-co-diphenylamine-4-sulfonate)　(PANDPS)　nanoparticles　with　good　self-stability　were　synthesized　by　chemical　oxidative　polymerization　of　aniline　(AN)　with　diphenylamine-4-sulfonate　(DPS)　in　HCl　aqueous　medium　without　any　external　additive.　The　variation　of　the　structure　of　the　copolymers　was　studied　by　changing　the　monomer　ratio,　oxidant/monomer　molar　ratio　and　polymerization　time.　It　is　found　that　the　particle　size　and　structure　of　the　copolymers　varies　with　the　polymerization　conditions.　The　PANDPS(50/50)　copolymer　nanoparticles　with　the　average　diameter　of　33　nm　were　synthesized　with　a　monomer　concentration　of　0.2　mol/L,　(NH4)2S2O8/monomer　ratio　of　1/4　in　1.0　mol/L　HCl　at　25°C　for　24　h,　whereas　copolymer　nanorods　(130　nm-140　nm　in　diameter　and　440　nm-1.35　μm　in　length)　were　obtained　during　the　polymerization　with　a　monomer　concentration　of　0.1　mol/L,　(NH4)2S2O8/monomer　molar　ratio　of　1/4　in　1.0　mol/L　HCl　at　25°C　for　72　h.