TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): High-purity silibinin is prepared by (A) taking Silybum marianum shell as a raw material, adding acetic ether to dissolve S. marianum shell, extracting general flavone and vacuumizing, where mass ratio of Silybum marianum shell to acetic ether is 1:3-1:3.2; and (B) dissolving, extracting, filtering and drying general flavone to obtain high-purity silibinin. The step (B) includes after adding water into general flavone to dissolve, taking sedimentation into ethanol solution, and dissolving to obtain silibinin crude product I; adding silibinin crude product I into ethanol solution and dissolving to obtain silibinin crude product II; and adding silibinin crude product III into absolute ethanol, dissolving, filtering by microhole, concentrating filtrate to reach 20-30% of total volume of the silibinin crude product II and the added absolute ethanol, devitrifying, filtering and drying to obtain high-purity silibinin. Preferred Components: The content of high-purity silibinin is mass percentage detected by dry product in the high performance liquid chromatography method. Preferred Method: The addition of acetic ether and extraction of general flavone in step (A) are preformed twice. The mass ratio of S. marianum shell to acetic ether is 1 1.7-1:1.8. The general flavone is extracted for 2 hours at the first time. The mass ratio of Silybum marianum shell to acetic ether is 1:1.3-1:1.4 and general flavone is extracted for 2 hours at the second time. The general flavone is extracted for first time, where extractor has self-circulating manner. The general flavone is extracted for the second time, where extractor has big circulating manner. The self-circulation and big circulation are circulated once at every 20-30 minutes, where each time is preformed for 10-15 minutes. The temperature for recycling general flavone is at 91-92 degrees C. The S. marianum shell taken as raw material in step (A) is crushed. The concentration of ethanol in step (A) is 50 mass%. The concentration of ethanol in the step (B) is 65 mass%. The adding quantity of ethanol solution in step (A) is 3 times of the quantity of general flavone. The adding quantity of ethanol solution in step (B) is 3 times of quantity of silibinin crude product I. The adding quantity of ethanol solution in step (C) is 10-12 times of quantity of silibinin crude product II.