The invention provides a method for preparing a strontium titanate film through an electrochemical method. The method comprises the following steps that firstly, a metallic titanium sheet is subjected to acid pickling at the room temperature; secondly, the titanium sheet subjected to acid pickling is washed thoroughly with deionized water and is polished by abrasive paper for metallograph until the surface has metallic luster, the titanium sheet is subjected to ultrasonic washing through deionized water, absolute ethyl alcohol and acetone, and the titanium sheet is washed with deionized water and then dried to be used; thirdly, the titanium sheet is immersed in an ethylene glycol solution containing NH4F and deionized water, the titanium sheet serves as an anode electrode, a platinum electrode serves as a cathode electrode, and direct current is exerted for anodic oxidation at the room temperature; fourthly, the titanium sheet subjected to anodic oxidation serves as an anode electrode, the platinum electrode serves as a cathode electrode, a Sr(NO3)2 solution serves as electrolyte, and direct current is exerted for a reaction at the room temperature; and fifthly, after the electrochemical reaction is finished, a sample is taken out and washed thoroughly with deionized water, and after the sample is subjected to thermal treatment, the strontium titanate film is obtained. The method is simple, the thickness and the structure of the strontium titanate film can be controlled easily, and batch preparation of large strontium titanate films can be achieved.