The influence of surface grease on the binding force of epoxy sprayed steel strand and cement mortar was studied by comparing the tensile strength of epoxy sprayed steel strand under five different conditions. The experimental results show that the surface grease of epoxy sprayed steel strand has a certain effect on the binding force of cement mortar. The steel strand with more grease on the surface has a poor binding force, while the steel strand with clean grease on the surface has a better binding force. In the actual process of unbonded prestressing tendons, the surface grease of epoxy steel strand should be cleaned to avoid affecting the tensile properties of unbonded prestressing tendons.