The flow characteristics of various flaps with slots is studied by solving the Reynolds averaged Navier-Stokes equations with two-layer zonal model,while the pressure distribution is measured by experiments.The results reveal that the flow structure of flaps with slots depends on the interaction of flows around two parts of the flaps with slots.The two flows have no intervention at porosity η=50%;but they interact stronly at η=20%,30%.The circulation zone downstream of the flaps becomes larger and has weaker turbulent intensity.