This paper deals with numerical simulations of an active feedback control of leakage-flow-induced sheet flutter in a narrow passage. In this paper, a new non-contact control device and active feedback control technique by using moving baffle-plates to suppress the sheet flutter are proposed and its numerical model is developed by using finite-segment method based on multi-body dynamics formulation. The control performance of the proposed control device and active feedback control method is evaluated by the numerical simulations. In the modeling of the system, the flexible sheet consists of some rigid bodies connected with rotational springs and dampers based on multi-body dynamics formulation. The nonlinear fluid forces acting on the rigid bodies are derived from the basic equations of leakage fluid flow in a narrow passage. The nonlinear equation of motion of the flexible sheet coupled with the fluid flow controlled by the moving baffle-plate actuators is calculated numerically. By the numerical simulations, it is shown that sheet flutter is effectively suppressed by the proposed non-contact control device and active feedback control. Moreover, the control performance is evaluated with changing controller gain and phase shift angle of the control signal.