The invention relates to a preparation method of an antique silk painting cultural relic. The preparation method comprises the following steps: 1) aging 40-50 parts by mass of white silk under an ultraviolet lamp aging oven for 10-15 hours and then putting the silk in a dark place to obtain archaistic silk; 2) preparing a pigment for painting, adding 1-3 parts by mass of adhesive material A to 80-100 parts by mass of plant pigment C1 and mixing evenly to obtain a pigment C2; 3) evenly applying the pigment C2 obtained in the step 2) to the archaistic silk obtained in the step 1) and naturally airing; 4) spraying 15-20 parts by mass of microprecipitation protective agent W1 to the archaistic silk obtained in the step 3), and after an organic solvent in the microprecipitation protective agent W1 evaporates, evenly applying 15-20 parts by mass of microprecipitation protective agent W2 to the archaistic silk; 5) naturally airing to obtain the antique silk painting. The preparation method of the antique silk painting cultural relic is capable of effectively imitating the ancient silk paintings and providing samples for aging research and protection work of the ancient silk paintings.