The leaf movement of the Venus flytrap possesses advantages such as rapid action, reversibility, easy control, and simple structure. Therefore, this paper draws inspiration from the rapid movement of Venus flytrap, and investigates its basic structure and kinematic characteristics at both the micro and macroscopic levels. At the microscale, the vascular system structure, cell size, and spatial arrangement of cells in the transverse and longitudinal directions of the leaf are observed and analyzed using plant sectioning and tissue clearing techniques. At the macroscale, the patterns of variation in horizontal displacement, velocity, acceleration, and opening angle of the leaf edge are analyzed using a high-speed camera and Kinovea image analysis software. Additionally, a non-contact full-field strain measurement system is employed to obtain the surface strain during the closure process of the Venus flytrap leaf. Based on a porous media model, the motion patterns of cell expansion deformation caused by moisture transport are investigated, as well as the bending deformation patterns of biomimetic flexible leaves under fluid influence. Finally, a biomimetic flexible leaf actuator is fabricated using 3D printing technology for experimental validation. The study demonstrates that the proposed biomimetic flexible leaf actuator, employing fluid-structure coupling simulation, is capable of achieving bending deformation within 1 second under a hydraulic pressure of 2 MPa, and the maximum bending angle is 32.27°. Moreover, the experimental results of the fabricated prototype of the biomimetic flexible leaf actuator align closely with the simulation results, confirming the feasibility and accuracy of the fluid-structure coupling simulation technique. The reproduction of the rapid closure motion of Venus flytrap leaves is achieved, showcasing the swift bending of the leaf during the closure process.