Flagellar motor is a molecular rotary motor,it plays central role on the structures and functions of bacterial flagella.The structure of flagellar motor was clarified on the whole,its stator and rotor were composed of five proteins:Mot A,Mot B,FliG,FliM and FliN.The driving force comes from transmembrane H⁺ or Na⁺ flux. At present its rotary dynamics and torque-generating mechanisms were understood preliminarily.As a perfect research model for molecular rotary motor,the further study of flagellar motor would be very helpful for realizing the mechanisms of bioenergetic conversion and cell motility,thus its study is of widespread importance for biology.