A solid phase synthesizing method of a dihydronaphthalene compound I belongs to the field of organic chemistry and comprises: 1, using 1% crosslinked polystyrene resin as a carrier to prepare a polystyrene-loaded selenium base succinimide reagent III; 2, under catalyzing of fluoroform sulfonic acid trimethyl estersil, using the III to induce olefin V to be subjected to intramolecular cyclization to form 3-polystyrene-loaded selenium base-1,2,3,4-tetrahydronaphthalene VI; 3, removing VI by an oxidant through oxidation without further separating, thereby directly obtaining dihydronaphthalene I. Raw materials are easy to obtain, the product yield is good, the purity is high, the operation is simple and convenient, the posttreatment is simple and the method has well industrial application prospect.