The invention belongs to the technical field of alloy materials, and particularly relates to a copper-nickel-tin alloy used for a socket and a preparation method thereof. The copper-nickel-tin alloy comprises the following components of, in percentage by weight, 8 wt%-12 wt% of Ni, 2.5 wt%-3.8 wt% of Sn, 0.07 wt%-0.16 wt% of Si, 0.02 wt%-0.09 wt% of B, 0.03 wt%-0.06 wt% of W, 0.01 wt%-0.02 wt% ofBe, and the balance Cu. According to the copper-nickel-tin alloy used for the socket, the components of the copper-nickel-tin alloy for the socket are optimized and adjusted, the elements have a synergistic effect, the strength, the corrosion resistance, the heat resistance and the elasticity of the copper-nickel-tin alloy can be remarkably improved, and the prepared copper-nickel-tin alloy can bestored for a long time in the air and can still maintain bright and beautiful appearance without darkening.