In order to study the mechanical properties of steel fiber reinforced recycled aggregate concrete（SFRAC） under direct shear， 138 specimens were designed and tested with the change parameters of specimen size， substitution rate of recycled aggregate and steel fiber volume fraction（V_f）. The whole process curves of direct shear load-displacement of specimen were obtained， and the influence rules of different variation parameters on peak shear force and compressive strength of steel SFRAC were analyzed. The conversion coefficient of SFRAC peak shear forces under different specimen sizes was obtained， and the shear strength formula of SFRAC was proposed. The results show that the peak shear force of SFRAC increases with the increase of specimen size. With the increase of V_f， the peak shear force of specimens with V_f=0% first increases and then decreases， and the peak shear forces of specimens with V_f=1.0% decreases. Steel fiber can improve the shear capacity of recycled concrete greatly， but it can only improve the compressive strength slightly. The calculated values of the proposed shear strength formula are in good agreement with the experimental values.