In order to study the bond slip relationship between recycled concrete and steel bar, 6 groups of reinforced recycled concrete pull out test were conducted. Along anchorage length of steel bar, a series of inner embedded strain gauges were arranged at different positions .Based on the test result, an investigation was conducted to study the influence of recycled coarse aggregate on anchoring strength and bond slip curves. The distribution of the bond stress and relative slip displacement along the anchorage length of steel bar are calculated, the position function and bond slip relationship along anchorage length are deduced. Finally, the bond slip constitutive equation considering position function is constructed, which provides reference for finite element analysis of recycled concrete.