Abstract: Silver-based alloys are significant light-load electrical contact materials (ECMs). The trade-off between mechanical properties and electrical conductivity is always an important issue for the development of silver-based ECMs. In this paper, we proposed an idea for the regulation of the mechanical properties and the electrical conductivity of Ag–11.40Cu–0.66Ni–0.05Ce (wt%) alloy using in-situ composite fiber-reinforcement. The alloy was processed using rolling, heat treatment, and heavy drawing, the strength and electrical conductivity were tested at different deformation stages, and the microstructures during deformation were observed using field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and electron backscatter diffraction (EBSD). The results show that the method proposed in this paper can achieve the preparation of in-situ composite fiber-reinforced Ag–Cu–Ni–Ce alloys. After the heavy deformation drawing, the room temperature Vickers hardness of the as-cast alloy increased from HV 81.6 to HV 169.3, and the electrical conductivity improved from 74.3% IACS (IACS, i.e., international annealed copper standard) to 78.6% IACS. As the deformation increases, the alloy strength displays two different strengthening mechanisms, and the electrical conductivity has three stages of change. This research provides a new idea for the comprehensive performance control of high-performance silver-based ECMs.