The layer jamming mechanism is widely applied to soft actuators but is limited by the non-fluid layer material with a narrow range of stiffness variation. Inspired by the excellent adhesive ability of geckos, the bionic adhesive flaps with tilted semicircular micropillars are designed for the layer jamming mechanism. A prototype of the layer jamming actuator based on the bionic adhesive flaps is fabricated. A variable stiffness theoretical model of the layer jamming structure is established, and the shear adhesive force of the bionic adhesive flap during detachment is calculated based on the Kendall viscoelastic band model. The measurement results of shear adhesive forces show that the critical shear adhesive forces of the bionic adhesive flaps are increased by a factor of 3.2 compared to the PET flaps. The variable stiffness performance of the layer jamming actuator based on bionic adhesive flaps is evaluated by two stiffness test methods, and the maximum stiffness reaches 8.027 N/mm, which is 1.5 times higher than that of the layer jamming actuator based on PET flaps, verifying the feasibility and superiority of the application of the bionic adhesive flaps to the layer jamming mechanism to improve stiffness.