In order to investigate the effect of uniaxial compressive stress on the damage of recycled concrete, real—time ultrasound tests were carried on recycled concrete with different recycled aggre—gate replacement ratio by using ultrasonic detecting technology.The rule of axial compressive damage altered with uniaxial compressive stress was studied by the uniaxial compression tests and real——time ultrasound tests of recycled concrete with different recycled aggregate replacement ratio.The results show that recycled aggregate replacement ratio has remarkable effect Oil the damage of recycled con—crete, and the axial compressive damage of recycled concrete can not be ignored before load get at ul—timate compressive stress.Based on the test results, a damage relational model of recycled concrete is established under considering the effect of uniaxial compressive stress and the initial compressive strength of recycled concrete at different recycled aggregate replacement ratio.