The invention discloses a synthesis method of 9, 9di [4 -(2-hydroxy ethoxy) phenyl] fluorene, and belongs to the technical field of chemical synthesis. 9-fluorenone, phenoxyethanol, a catalyst and a cocatalyst are stirred and heated to reflux in an alkane solvent, generated water is removed from a reaction solution in an azeotropic manner while reaction is performed, water is added for dilution after the reaction is finished, the mixture is stirred uniformly, cooled, crystallized and filtered, a filter cake is rinsed and dried, and a 9, 9-di [4- (2-hydroxy ethoxy) phenyl] fluorene finished product is obtained; standing and layering the crystallized mother liquor obtained by filtering, removing a water phase, distilling an organic phase to recover the alkane solvent, and rectifying a concentrate to recover phenoxyethanol. The method has the advantages of cheap and easily available raw materials, simple operation, good atom economy, high synthesis yield, good product quality, environmental friendliness and the like, and is suitable for industrial application.