Abstract: Effects of solid solution time on the organization and mechanical properties Cu-Ni-Si-Mg alloy was studied by optical microscope, scanning electron microscopy, energy spectrum and other analysis of tests methods. The results show that, with the prolonging solid time, the cold rolled plate organization is witnessed a process of recovery, re-crystallization and grain growth, back solution of the secondary phase particle. The yield strength and tensile strength of the alloy increase at first, then decrease. Finally, they tend to be steady. The variation of electrical conductivity rate is observed at a likewise tendency. The elongation reaches its maximize of 52 % at the time of 60 s.