Aiming　at　the　problem　of　high　precision　and　high　safety　estimation　of　state　of　power　(SOP)　of　high-rate　lithium-ion　power　battery　in　the　application　of　special　operation　vehicle,　this　paper　analyses　the　working　characteristics　of　the　high-rate　lithium-ion　power　battery,　and　builds　the　second-order　RC　equivalent　circuit　model　of　the　battery.　The　recursive　least　squares　(RLS,　Recursive　Least　Squares)　algorithm　is　used　to　identify　battery　parameters　online,　and　the　SOC　algorithm　based　on　the　extended　Kalman　filter　and　the　SOP　algorithm　are　used　for　joint　estimation.　This　algorithm　is　used　to　solve　the　problem　that　the　maximum　allowable　power　of　the　actual　battery　caused　by　the　degradation　of　battery　life　is　difficult　to　calculate　and　even　causes　the　problem　of　safe　fire　accidents.　Combined　with　the　correction　algorithm　in　practical　engineering,　it　ensures　the　efficiency　and　safety　of　the　SOP　estimation　during　the　entire　life　cycle　of　the　electric　vehicle.　This　research　has　an　important　significant　guiding　in　engineering　practice.　©　2021　IEEE.