Aiming at the surgical treatment of anal fistula, a degradable anal fistula sealing device was designed. L-polylactic acid specimens with different molecular weights and different groups were prepared by high-temperature melting method. The stress-strain curve of the material was obtained by tensile test, and the best material for the sealing device was determined. Finite element simulation analysis software ABAQUS was used to systematically study the stress-strain distribution and radial support force during the sealing process. The results showed that the elastic modulus of L-polylactic acid is the highest with the molecular weight of 1.1 million and the group is ester-sealed. The maximum stress of the sealing device in the process of sealing did not exceed its allowable stress 4.55 kPa. In the initial contact stage, the stress was only concentrated in the area around the sealing device, and the further away from the contact center, the greater the stress value was. The contact stress diffused from the contact center to all sides in the form of ring wave with the continuous intrusion of the sealing device. The sealing device basically maintained the initial shape and did not have obvious extrusion deformation.It would not be crushed in the sealing process and had a good sealing effect.