The invention discloses a preparation method of 2-amino-9,9'-2-substituted fluorene, belonging to the field of organic chemical synthesis. The preparation method comprises the following steps: preparing 2-nitryl-9,9'-2-substituted fluorene by carrying out nitration reaction on fuming nitric acid by taking 9,9'-2-substituted fluorene as raw materials and methylene dichloride as a solvent; and then, preparing 2-amino-9,9'-2-substituted fluorene by carrying out reduction reaction by taking Pd-Al2O3 as a catalyst and hydrogen or hydrazine hydrate as a reducing agent in short-chain alkanols. In the method, the Pd-Al2O3 with high reaction activity, high reaction speed, short reaction time, good selectivity and less byproducts is used as a catalyst; except for nitrogen and water, any substance which is harmful to the environment is not produced; and environment protection, simple aftertreatment and high transformation ratio are achieved. By introducing different alkyl substituents on fluorene, the intermolecular accumulation can be efficiently lowered and the solubility property of molecules can be improved so that an obtained 2-aminofluorene derivative can be used for the design and the synthesis of organic photoconducting materials.