Abstract: Aiming at the problem that the ribs of the expandable decelerator are prone to bending and deformation under complex aerodynamic load, a deployable umbrella-shaped decelerator with stiffness adaptability is proposed, and the bending stiffness of the ribs is enhanced with the increase of external aerodynamic load by reasonably arranging the pretensioned flexible cable. Firstly, based on the load equation, the theoretical model of the support structure of the decelerator is established, and the principle of stiffness adaptability is analyzed. Secondly, the finite element analysis software is used to create a control model of cable-free and cable-containing decelerators to verify the stiffness adaptability of the cable-containing decelerator. Finally, the differential equation of motion and virtual prototype model is established to analyze the unfolding process of the decelerator. The analysis results show that under the action of the pretensioned flexible cable with a diameter of 10mm and an initial stress of 10MPa, the maximum deflection of the rib changes with the load curve into a monotonically increasing smooth concave curve, and the curvature gradually decreases with the increase of the initial stress of the pretensioned flexible cable. The maximum deformation of the whole cable-containing decelerator increases steadily at low speed in the 0~60% ultimate load range, and the maximum deflection decreases by more than 50%, showing relatively ideal stiffness adaptability.