The invention discloses a device for replacing a steel needle with Z-direction steel needle three-dimensional fabrics and buckling fibers. The device comprises a movable workbench, a steel needle replacing mechanism, a wire feeding mechanism, a locking mechanism, a tension control mechanism and a control system, wherein the movable workbench is driven by a servo motor, is composed of a Z-directionmovable platform and a Y-direction movable platform, and is provided with a three-dimensional fabric clamping device; the steel needle replacing mechanism drives a special clamp X to move in an X-direction through the servo motor, so that needle clamping is completed; the wire feeding mechanism drives a wire feeding needle to move in the X-direction through the servo motor, so that yarns are fedinto the three-dimensional fabrics; the locking mechanism drives a crankshaft rocking bar mechanism through a step motor to realize swinging a hook needle back and forth to complete locking; and the tension control mechanism rotates back and forth through the step motor to drive a yarn storage to move back and forth, so that yarn storage and tension control are completed. The device is compact instructure, is novel and reasonable in design, realizes automation of replacing the steel needle with Z-direction steel needle three-dimensional fabrics and buckling fibers, improves production efficiency and product consistency, is high in practicability, is good in using effect, and is convenient to popularize.