Dynamic stall due to unsteady motion is a common phenomenon in nature and engineering fields. The leading-edge vortex (LEV) or dynamic stall vortex (DSV) is the key structure determining the variation of aerodynamic force and moment in this process. In this talk, we will introduce dynamic models to describe LEV evolution and vortex lift mechanism, where effective velocity and effective angle are found to be two dominant parameters. Then, critical indicators are proposed for whole-life monitoring of dynamic stall, including formation of laminar separation bubble, LEV initiation, LEV centre position and the detachment of LEV. Finally, unsteady flow control strategies based on vortex manipulation are proposed to delay dynamic stall and maintain high lift.