The invention relates to a special hot-dip plating alloy for a coating on the surface of a titanium alloy part, wherein the hot-dip plating alloy contains the following components by mass percentage: 8-24% of Si, 1.2-3.1% of Zn, 0.02-0.5% of RE, 0.5-3.2% of Mg, 0.05-1% of Fe, 0.05-0.5% of Cu, 1.0-2.0% of Mn, 0.5-2.0% of Cr, 0.02-0.5% of Zr, 1-2% of nano-oxide particle reinforcing agent and the balance of Al and inevitable impurities, and the nano-oxide particle reinforcing agent is selected from one or two of TiO2 and CeO2. The adoption of the hot-dip plating alloy produced by the invention can form the coating which has corrosion resistance and good wear resistance, and is well metallurgically bonded with a matrix on the surface of the titanium alloy.