The invention discloses a mirror surface plating solution and an immersion plating method. The mirror surface plating solution comprises a photo stimulated activator and an immersion plating solution; the photo stimulated activator comprises the following raw materials: triethanolamine, gelatin, stannous chloride, a phosphate promoter and an alkyl coupling agent; the immersion plating solution comprises the following raw materials: silver nitrate, copper chloride, glucose, hydrazine hydrate, methane sulfonic acid, sodium hydroxide, gelatin and pyridine. The mirror surface plating solution adopts an aqueous solution, does not contain traditional cyanides, volatile organic solvents, and heavy metals such as lead, chromium and nickel, has no harmful substance emission problem, and is environmental-friendly, the immersion plating process is simple, the operation is easy, electricity utilization and heating are not needed, the working efficiency is improved greatly, the production cost is reduced, no expensive equipment is needed, and the immersion plating process is a low-investment and energy-saving new process.