Abstract: In this study, an optimal combination of mechanical strength, stress relaxation resistance, and conductivity was achieved in a Cu–Be alloy by controlling the precipitate distribution. The precipitation behaviors of the Cu–Be alloy aged at 360°C revealed that the size, morphology, and distribution of precipitated phases can be effectively controlled, enabling the alloy to attain a tensile strength exceeding 1043 MPa. With a reasonable proportion of precipitates, the corresponding electrical conductivity and stress relaxation resistance can reach more than 30.8% IACS and 96.7%, respectively. By correlating the morphology, size, and distribution of precipitated phases with the stress relaxation resistance of the Cu–Be alloy, kinetic equations for the stress relaxation behaviors of the alloy were established in this study. Correspondingly, the stress relaxation rates (SRR) of the alloy were predicted after different stress relaxation times.