The present invention belongs to the field of pharmaceutical chemistry, and discloses a pumiloside preparation method. According to the pumiloside preparation method, strictosamide is adopted as a raw material, and is subjected to illumination placing under an oxygen-containing sealing condition to obtain pumiloside. According to the present invention, the strictosamide content in nauclea officinalis is high, and a column chromatography method is used to separate so as to obtain the strictosamide, such that the raw material sources of the method are wide; and the preparation method has characteristics of simple operation and green environmental protection, and the pumiloside yield is more than 70%.