The present invention relates to a new steroid compound extracted and separated from sponge of the South China Sea and its extraction method. Said invention provides its structure formula and its extraction method includes the following steps: soaking sponge in ethyl alcohol to make extraction, concentrating extract, making it be dispersed in water, using ethyl acetate to make extraction, concentrating the obtained ethyl acetate solution, silicon gel column chromatography for three times and dextran gel LH-20 column chromatography once, then using petroleum ethyer-acetone or chloroform-methyl alcohol to make crystallization so as to obtain the described compound with a certain action of resisting virus. |