An arc-ablation resistant tungsten alloy switch contact and preparation method is disclosed. A contact member has a three-layer structure, wherein a first layer is a hydrophobic rubber layer, a second layer is a sheet metal layer, and a third layer is a tungsten alloy chemical deposition layer. A plating bath adopted in the chemical deposition contains 25-125 g/L soluble tungsten compound, 0-60 g/L soluble compound of a transition metal like ferrum, nickel, cobalt, copper or manganese, and 0-30 g/L soluble compound of tin, stibium, lead or bismuth. When a layered complex of the hydrophobic rubber layer and the sheet metal layer is chemically plated by the plating bath, a tungsten alloy plated layer is selectively deposited on a metal surface, and chemical deposition of the tungsten alloy does not occur on a surface of the hydrophobic rubber fundamentally.