Abstract: To evaluate the service reliability of Carbon Fiber Reinforced Plastic (CFRP) composite tubes used in spacecraft structure,static three-point-bending and creep tests of the CFRP tube are performed. At first,experimental tests of bending modulus and bending rupture strength,500-hour-long constant temperature creep,-60 ℃～100 ℃ and -160 ℃～80 ℃ thermal cyclic creep are conducted for the tube respectively. Based on the testing results,long-term creep deformation of the tube is predicted,using the time-temperature-stress superposition principle,the derived creep master curves as well as a phenomenal Findley model. Then,assessment on the mechanical strength and load-carrying capacity of the CFRP tube is made according to a maximum strain criterion. Results show that the CFRP tube can meet the creep deformation and strength requirements under the long-term service lifetime.