The invention relates to a silver-plated polytetrafluoroethylene microporous film. The silver-plated polytetrafluoroethylene microporous film comprises a polytetrafluoroethylene microporous film bodyand a silver-plated layer attached to the surface of the polytetrafluoroethylene microporous film body, and a solid solution is formed between the silver-plated layer and the polytetrafluoroethylene microporous film body. The invention further relates to a preparation method of the silver-plated polytetrafluoroethylene microporous film, and the preparation method comprises the steps that (1) polytetrafluoroethylene resin powder and an extrusion additive are mixed, then extrusion, calendaring, degreasing and stretching are conducted, and a product A is obtained; (2) the surface of the product Ais plated with silver, and a product B is obtained; and (3) the product B is sintered, and the silver-plated polytetrafluoroethylene microporous film is obtained. According to the silver-plated polytetrafluoroethylene microporous film, sintering is conducted after silver plating, thus the solid solution is formed between the silver-plated layer and the polytetrafluoroethylene microporous film body, the bonding force between the silver-plated layer and the polytetrafluoroethylene microporous film body is much larger than that of mechanical engaging in the prior art, and accordingly, the plating layer bonding performance of the silver-plated polytetrafluoroethylene microporous film is optimized; and meanwhile, internal stress in the silver-plated layer is further eliminated, and thus the bonding force between the silver-plated layer and the polytetrafluoroethylene microporous film body is further improved.