The invention provides a preparation method of a novel organic hole transport layer perovskite solar cell. The prepared solar cell device structure comprises a substrate, an anode, a hole transport layer, a photoactive layer, an electron transport layer, a cathode modification layer and a cathode from bottom to top, wherein the hole transport layer is prepared into an organic small molecule monomer BTCV by adopting an organic chemical synthesis method, the preparation method comprises steps of dissolving the BTCV in organic solvent, then spin-coating the BTCV on a glass substrate, and carryingout polymerization cross-linking reaction by adopting high-temperature annealing or ultraviolet lamp irradiation to form a reticular hole transport layer which is used for transporting holes and improving the photoelectric conversion efficiency of the cell, and photoelectric conversion efficiency can reach 17.58%, the organic small molecular monomer BTCV has advantages of simple synthesis steps,low cost, high yield and stable properties, can be commercially produced, and greatly lowers the cost of the perovskite solar cell. The organic hole transport material micromolecular monomer BTCV canfurther be applied to preparation of other photovoltaic devices.