Abstract: Fiber composite pipe is a key component in a certain type of equipment, and its development focuses on the determination of damage tolerance. To study the damage characteristics of fiber composite pipe under constant loads, based on the essential failure model (matrix cracking, delamination, fiber breakage and debonding) of this composite material based on reinforced fiber, combined with the working characteristics of the material, the pipe internal morphology under different loading conditions from various angles was observed and tested using visual method, metallographic method, vibration test method and X-ray microscopy method to indirectly reflect the effect of constant loads on the mechanical behavior of tube. According to the test results, the failure process of the pipe was described preliminarily. The failure reason of the pipe under constant loads is determined to be the debonding of the fiber and the matrix. Some suggestions for improving the process are put forward.