New　nano/submicron　branched　platinum　(B-Pt)　was　readily　synthesized　by　auto-reduction　reflux　of　H2PtCl6　solution　mixed　with　poly(ethylene　oxide)-poly(propylene　oxide)-poly(ethylene　oxide)　(Pluronic　F127,　PEO100PPO65PEO100).　The　as-prepared　B-Pt　shows　many　interconnected　fractal　twigs　with　the　diameter　of　each　branch　at　nano-level　though　the　whole　B-Pt　array　is　relatively　large　at　submicron　size.　High　resolution　transmission　electron　microscopy　(HRTEM)　shows　that　the　B-Pt　generally　exposed　(111)　planes　and　possesses　a　high　density　of　edges　and　corners,　widespread　lattice　distortions,　step　and　suspension　atoms,　which　are　all　beneficial　for　electrocatalysis.　Electrochemical　tests,　comparing　the　kinetic　current,　further　confirmed　that　the　oxygen　reduction　reaction　(ORR)　activity　of　the　B-Pt　was　better　than　that　of　current　commercial　Pt　black　and　Pt/C　catalysts.　The　copolymer　serves　as　reducing,　protecting　and　orienting　agent　at　the　same　time　and　the　growth　mechanism　of　B-Pt　is　described　in　detail.