The microstructure,tensile strength,bonding properties,high temperature resistance of strain isolation pad,which was prepared by needle process with aramid fibers as material are investigated.The results show that strain isolation pad has good coordinate deformation capacity and tensile strength when the punch density is 35 punches/cm² and the material density is 0.18 g/cm³.When the heating temperature is lower than 200℃, there is no significant change of structures and intensity. At the wind tunnel environment, maximum surface temperature is 1500℃, the apparece of the thermal protection system is complete with no cracks and no looseness after the wind tunnel test, the test results validate the reliability of strain isoation pad.