The invention discloses a method for directly preparing N,N-bislactose-1,10-decamethylene diamine by adopting one-pot reaction, belonging to the technical field of synthesis of glycosyl surfactants. The method comprises the steps of: mixing lactose with decamethylene diamine in a molar ratio of (2.0-2.5):1, adding an alcohol and water mixed solvent with a volume ratio of alcohol to water being (50-75):100, wherein the ratio of the total mass of the lactose and the decamethylene diamine to the mass of the mixed solvent is 1:(4-6); and mechanically stirring for 20-24h at a normal temperature, heating to 45-60 DEG C in a water bath, reacting for 1-2h, cooling and placing for 0.5-2h, separating out a large quantity of solids, filtering, washing, re-crystallizing with absolute ethyl alcohol, freezing and drying to obtain a white solid, i.e. N,N-bislactose-1,10-decamethylene diamine. The method has the advantages of low price and easy obtaining of raw materials, simple and mild reaction conditions, convenience and safety in operation, simpleness in post-treatment, high production yield, suitability for industrial production, and high implementation value.