In　this　study,　we　develop　a　wearable　device　which　uses　a　novel　strategy　for　Automatic　Activity　Recognition　(AAR)　system.　This　new　system　will　not　only　reduce　power　consumption,　but　also　improve　the　accuracy　and　stability　of　the　system.　This　system　will　be　linked　with　wireless　network　(Bluetooth)　and　passing　the　data　processed　by　the　AAR　system　from　the　device　to　smartphone.　The　novel　strategy　for　the　AAR　system　mainly　focuses　on　the　processing　on　the　MCU　and　building　a　model　for　the　recognition　of　human　activity　efficiently.　In　this　paper,　we　introduce　the　development　of　the　wearable　device　based　on　the　AAR　system　which　has　friendly　design　and　stable　performance.