Method for preparing the nanometer aurum solution

This invention discloses a method for preparing the nanometer aurum solution which includes the following processes: (1) charging chloroauric acid into the deionized water, then charging polyvinyl pyrrolidone and sodium dodecyl sulfate to form a mixture solution after chloroauric acid is dissolved, in which the mass concentrations of chloroauric acid, polyvinylpyrrolidone and sodium dodecyl sulfate are 0.01 to 0.5%, 0.02 to 2.0% and 0.0001 to 1.0% respectively (2) at room temperature, charging 0.01 to 0.5% concentration of aqueous solution of hydrazine hydrate into the mixture solution of step (1) while agitating, when pH value reaches 6.8 to 7.0, ceasing the charge of hydrazine hydrate aqueous solution, then continuing to stir 20 to 30 minutes to obtain the nanometer aurum solution. The advantages of this invention: are that the preparation is carried out under room temperature, process is simple, the particle size of nanometer aurum in the nanometer aurum solution is 10 to 100 nm and precipitation is not easy to occur due to small aurum particle size.