The invention discloses a method for producing 1,1,3-trichloroacetone, belonging to the technical field of chemical product preparation. The method comprises the following steps: with acetone as a raw material, synthesizing 1,1,3-trichloroacetone in an inert solvent through photocatalytic chlorination, recovering a solvent, acetone, monochloroacetone, 1,1-dichloroacetone and other light components from a chlorination solution in a rectification manner, separating the intermediate component 1,3-dichloroacetone from 1,1,3-trichloroacetone in a simulated moving bed filled with an adsorbent to obtain 1,1,3-trichloroacetone, conducting eluting with a desorption agent to obtain a desorption solution containing 1,3-dichloroacetone and 1,1,3-trichloroacetone, distilling the desorption solution to remove the solvent, and then returning the desorption solution to a chlorination kettle for indiscriminate application. The method has the characteristics of mild reaction conditions, high reaction rate, high selectivity of 1,1,3-trichloroacetone, low wastewater discharge amount, environment-friendly process and the like.