The invention relates to a technology for synthesizing SrTiO3 nano-powder through a mechanochemical method. The technology at least comprises the following steps: 1, taking a proper amount of each of strontium oxide and titanium dioxide raw materials, respectively dumping the raw materials into beakers, putting the beakers in an oven, and drying for 12h; 3, uniformly mixing the above two powders with a molar ratio of 1:1; 3, adding the above obtained powder mixture and tungsten carbide balls to a pot, wherein the total volume of the powder mixture and the tungsten carbide balls does not exceed 2/3 of the total volume of the pot, and a mass ratio of the powder mixture to the tungsten carbide balls is 20:1; 4, turning on a power switch, and uncovering the cover of a high-energy ball mill; 5, operating according to the flow of a high-energy ball milling experiment; 6, setting parameters comprising a rotating speed of 200rpm and a cycle period of 30min; 7, clicking a start button for the working starting of the ball mill; 8, uncovering the cover of the high-energy ball mill and the cover of the ball milling pot 24h later, sampling, cleaning the ball milling pot with alcohol, and drying for later use; and 7, turning off the power switch. The SrTiO3 nano-powder synthesized in the invention has the characteristics of low energy consumption, high purity, small particle size, high automation degree, good quality consistency and repetitiveness, less pollutant emission and the like.