The invention provides a method of preparing glycol by using a one-step ethylene method. The method comprises contacting ethylene, and an aqueous hydrogen peroxide solution with a catalyst containing titanium-silicon molecular sieves in an organic solvent under an oxidation reaction condition, wherein the contact is carried out in the presence of a surfactant. The method provided by the invention can directly use the ethylene and the aqueous hydrogen peroxide solution as raw materials, and directly prepare the glycol under the catalysis of the catalyst containing the titanium-silicon molecular sieves; and is high in conversion rate of the ethylene and in selectivity of the target product glycol.