In order to reasonably design and utilize recycled aggregate concrete, the larger porosity at the interface of primary aggregate, the pores and microcracks at the mortar and the aggregate interface effect were considered in the homogenization process of recycled aggregate concrete. A set of models that can predict the elastic modulus of recycled aggregate concrete with initial defects under aggregate interface effects was also developed by combining with the torsional deformation principle, Mori-Tanaka method, differential method and Christensen’s three-phase model. The calculation results show that with the increase of recycled aggregate replacement rate from 0% to 100% (mass fraction), the elastic modulus of recycled aggregate concrete decreases by 24.4%, and the decrease of elastic modulus of new mortar and primary aggregate also lead to the decrease the elastic modulus of recycled aggregate concrete by different degrees. The prediction model can better predict the elastic modulus of recycled aggregate concrete with initial defects under the interface effect, and realize parametric analysis.