The　transmission　system　has　an　important　influence　on　the　dynamic　performance,　endurance　mileage,　and　energy　saving　in　an　all-electric　vehicle.　This　article　proposes　an　innovative　two-speed　seamless　dry-friction　automatic　transmission　system　to　improve　the　dynamic　performance　and　endurance　mileage　of　an　all-electric　vehicle　with　the　existing　battery　technology.　The　proposed　system　consists　of　two-stage　epicyclical　gear　sets　without　outer　ring　gears,　a　dry-friction　clutch,　and　a　brake　band,　realizes　a　seamless　shifting　between　any　two　speeds　in　an　electric　vehicle.　Based　on　the　working　principle　and　dynamic　modeling　of　the　proposed　seamless　dry-friction　automatic　transmission　system,　the　ratio　optimization　was　carried　out　to　improve　the　dynamic　performance　and　the　power　consumption　at　the　same　time,　and　the　combination　of　the　weight　ratio　method　and　the　multi-island　genetic　algorithm　method　was　introduced　to　solve　the　optimization　problem.　It　is　shown　both　theoretically　and　experimentally　that　the　proposed　seamless　dry-friction　automatic　transmission　method　demonstrates　a　better　dynamic　performance　and　shifting　comfort　when　compared　to　the　automated　manual　transmission　with　same　transmission　ratio.　©　2018,　©　The　Author(s)　2018.