The invention discloses a silver-based circuit board with electroless nickel-palladium-gold plating and a preparation method thereof. The silver-based circuit board includes a silver-based substrate, and the surface of the silver-based substrate is sequentially plated with a nickel layer, Palladium layer, gold layer. The preparation method includes the following steps: performing micro-etching, pickling, pre-dipping, palladium activation, and post-dipping pre-treatment on the cleaned silver-based substrate in sequence, and then performing pre-treatment on the pre-treated silver-based substrate in sequence. Electroless nickel plating, electroless palladium plating, and electroless gold plating are silver-based circuit boards containing nickel-palladium-gold coating. Compared with traditional copper-based electroless nickel-palladium-gold plating, the thickness of nickel-palladium-gold electroless plating can be greatly reduced, thereby saving The use content of metals, while avoiding the problem of pollution to the environment. Furthermore, with the silver base as the base, the entire product has stronger electrical and thermal conductivity, higher sensitivity, longer life, and better overall performance.