TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The plant containing eta -viniferin is grape vine, naturally dried in shade for 1-3 months. The macroporous resin is D101-type macroporous resin, AB-8 type macroporous resin or D102 type macroporous resin.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The chromatographic column is alumina or silicone chromatographic column. The particle size of silicone in chromatographic column is 200-300 meshes. The chloromethane is dichloromethane or trichloromethane. Preferred Method: The samples are loaded by wet method during chromatographic column packaging. The gradient elution is carried out using chloromethane and methanol mixed solution sequentially in a volume ratio of 19:1, 16:1, 13:1 and 10:1, where the eluate containing resveratrol is collected while eluting using chloromethane and methanol mixed solution in a volume ratio of 19:1 and 16:1, and the eluate containing eta -viniferin is collected while eluting using chloromethane and methanol mixed solution in a volume ratio of 13:1 and 10:1. The amount of eluent used during each elution is 2-4 bed volumes and the eluent flow rate is controlled to 0.5-1.5 bed volume/hour. The step (ii) comprises concentrating the eluate comprising eta -viniferin crude product, drying at 40-50 degrees C, dissolving the obtained eta -viniferin crude product in methanol, loading samples into Sephadex (RTM: Cross-linked dextran gel) column by wet method, and performing column chromatography to obtain eta -viniferin-containing eluate, diluting using equal volumes of distilled water, volatilizing methanol in eluent at room temperature to initiate crystallization, cooling to 2-6 degrees C, allowing to stand, completing crystallization, and centrifuging and separating to obtain eta -viniferin monomer of purity greater than or equal to 98%, where the Sephadex (RTM: Cross-linked dextran gel) column is Sephadex LH-20 (RTM: Hydroxypropylated dextran) and the eluent flow rate is 1-2 bed volumes/hour. The solid mixture of resveratrol and eta -viniferin is prepared by: (a) crushing plant containing eta -viniferin to -20 meshes, adding an extraction agent, and extracting at 20-60 degrees C for 0.5-1 hour to obtain an extract, where the liquid-solid ratio is 4-6 ml/g, where the extraction agent comprises water and organic solvent in a volume ratio of (3-5):(15-17) and the organic solvent is ethanol, methanol or ethyl acetate; and (b) centrifuging the extract at a speed of 3000-5000 revolutions/minute, purifying supernatant by performing chromatography using a macroporous resin, sequentially eluting using water and ethanol, collecting the ethanol eluate, and concentrating and drying at 50-60 degrees C to obtain resveratrol and eta -viniferin solid mixture; or removing organic solvent from the extract obtained in step (a) at a temperature less than 60 degrees C, adding equal volumes of extraction agent, extracting, and concentrating and drying organic phase at 40-60 degrees C to obtain resveratrol and eta -viniferin solid mixture, where the extraction agent is ethyl acetate when the organic solvent in the extraction agent is ethanol or methanol, or the extracting agent is chloroform or methylene dichloride when the organic solvent in the extraction agent is ethyl acetate. The extraction is ultrasonic extraction or reflux extraction. The chromatographic purification method in step (b) comprises sampling at a rate of 2-3 bed volumes/hour, completing sampling, eluting using 1-3 bed volumes of water, then eluting using 2-6 bed volumes of ethanol, collecting ethanol eluate, vacuum concntrastign and vacuum drying at 50-60 degrees C to obtain solid mixture of resveratrol and eta -viniferin, where the concentration of ethanol is 70-90 vol.%.