The phase transformation kinetics of Cu-Be-Co-Zr alloy during aging treatment was investigated. Based on the relationship between electrical conductivity and volume fraction of precipitates, the phase transformation ratios of Cu-Be-Co-Zr alloy aged at 480 °C for different holding time (0, 30, 60, 120, 180, 240, 360, 480, and 600 min) were calculated. The kinetics equation of phase transformation and the electrical conductivity equation were derived. The isothermal transformation kinetics S-curves of Cu-Be-Co-Zr alloy was drawn. By the integral equation of solid thermal decomposition reaction mechanism, the phase transformation mechanism of Cu-Be-Co-Zr alloy is controlled by three dimensions of diffusion.