The invention relates to a high-speed object flexible capturing device and a capturing method. The flexible capturing device is manufactured by sewing a flexible textile material. The flexible capturing device mainly comprise a main body structure made from silk, a primary bearing network structure formed by a transverse reinforcing band and a longitudinal reinforcing band and an energy-absorbing structure formed by a torn suture portion. The high-speed object capturing method provided by the invention comprises the steps: placing a capture bag body between a separated object and an accelerated object; initially absorbing the kinetic energy of the separated object by means of the torn suture portion; and absorbing residual kinetic energy of the separated objected by the longitudinal reinforcing band and the capturing bag body. Compared with a conventional rigid capturing device, the device provided by the invention has the advantages of light weight, small volume, small impact, no separated object, no pollution, no noise, good safety and the like. The device provided by the invention is suitable for recovering various high-speed separated objects, and can serve as a means of capturing and recovering the separated object of an aerospace vehicle, so that the system safety is improved.