NOVELTY - Sub-critical water extracting chilli slag biological active substance involves 1) pretreatment of raw materials by: mixing crushed hot pepper dreg naturally air drying or drying at 100 degrees C, and then sieving through 40-80 meshes sieve; 2) sub-critical water extracting; 3) centrifuging the extracting liquid at 3500-6500 revolutions/minute for 15-30 minutes, and taking the supernatant; 4) filtering; and 5) concentrating.    USE - For sub-critical water extracting chilli slag biological active substance (claimed).    ADVANTAGE - The method is green and environmentally-friendly. The extraction efficiency is high, the production cost is low, and has great practical value and social and economic benefits. The method can extract several phenol and biologically active substance in the pepper residue with subcritical water, and compared with organic solvent, the extraction efficiency is high.    DETAILED DESCRIPTION - Sub-critical water extracting chilli slag biological active substance involves 1) pretreatment of raw materials by: mixing crushed hot pepper dreg naturally air drying or drying at 100 degrees C, and then sieving through 40-80 meshes sieve, 2) sub-critical water extracting by: taking step (I) of slag in extraction kettle, adding into deionized water which is 30-70 times of the hot slag in mass to the extracting kettle, where the pressure is 4-7 Mpa, the extraction temperature is 100-200 degrees C, and the extracting time is 15-90 minutes, obtaining extracting solution, 3) centrifuging the extracting liquid at 3500-6500 revolutions/minute, centrifuging for 15-30 minutes, taking the supernatant, 4) filtering: after centrifuging filtering the supernatant obtained by micro-filtration membrane, to obtain filtrate, 5) concentrating: concentrating the filtrate obtained in the step (4) by adding the filtrate in a rotary evaporator at 80 degrees C, where the rotating speed is 800 revolutions/minute, and the vacuum degree is 0.1 Mpa under the condition of, concentrating the filtrate until it is dry.