In recent years, researchers have found that separation control could increase the mean lift, decrease the drag, delay stall, reduce noise and influence the transition to turbulence, which has a significant economic and ecological impact on society, and it has been used extensively in the design of unmanned aerial vehicles (UAVs) and micro aerial vehicles (MAVs), which operate at low Reynolds numbers. In this paper, the passive separation control of a NACA0012 airfoil at Reynolds number Re = 1000 using self-adaptive hairy flap is investigated. The fluid motion is obtained by solving the discrete lattice Boltzmann equation, the dynamics of the flaps are calculated by the finite element method (FEM), and the coupling of flap dynamics and flow dynamics is handled by the immersed boundary method (IBM). Aerodynamic performance is quantified by the mean drag and mean lift of the NACA0012 airfoil. The influence of the flap parameters (quantity, length, rigidity and position) on the aerodynamic performance is investigated and a mean drag reduction and lift increment under a certain circumstance are observed.