The invention discloses a preparation method of nerolin. In order to overcome the defects that an existing preparation method of the nerolin has many byproducts, low product purity and limited production application, the preparation method comprises the following steps: generating nerol peroxide by carrying out photosensitized oxidation on nerol; recycling a solvent; reducing the nerolin peroxide into dinerol; inducing the dinerol by acid to generate nerolin; and purifying the nerolin. The preparation method is used for preparing nerolin, and is high in raw material conversion ratio, short in process route, gentle in reaction condition, energy-saving and environment-friendly, few in byproduct and high in product purity, so that an applied range of the nerolin is expanded, and the benefits are remarkably improved. According to the test and detection results, the mass fraction of the nerolin is 96%-98.5%, and the yield of the nerolin is 78-83.5%.