The invention discloses a one-pot method for preparing sarpogrelate hydrochloride photodegradation impurities I, II, III and IV. The method comprises the steps as follows: S1, photodegradation: 2-4 mg/mL of a solution is prepared by dissolving sarpogrelate hydrochloride in water, is treated at the high temperature of 80-90 DEG C for 1-2 h and then sequentially irradiated by a 1200,000-lux cold white fluorescent lamp for 4-6 h and a 200 Wh/m<2> ultraviolet fluorescent lamp for 3-5 h, finally, the degraded solution is concentrated and frozen to dryness, and a degraded mixture is obtained; S2, high-speed countercurrent chromatography: the degraded mixture is dissolved with a fixed phase and a mobile phase with the same volume to serve as a sample solution, ethyl acetate-ethanol-water-formic acid (4:1:5:0.025, v/v/v/v) serves as a two-phase solvent system, the upper phase is the fixed phase, the lower phase is the mobile phase, and the impurities I, II, III and IV are prepared through one-time separation under the conditions that the main engine rotational speed is 800 r/min, the flow velocity is 2.0 mL/min and the detection wavelength is 272 nm. The method adopts few steps and has high efficiency.