The invention provides a synthetic method of a spiro 4-hydropyrazole compound. An alkynyl-linked p-toluenesulfonyl hydrazone compound is used as a raw material, and reacted by one step through catalysis without a catalyst in an organic solvent to obtain a crude product of the spiro 4-hydropyrazole compound, and the crude product is washed with the organic solvent to obtain a pure product of the spiro 4-hydropyrazole compounds with different structures. The spiro 4-hydropyrazole compound disclosed by the invention has the advantages of no catalysts, easily synthesized raw materials, high reaction yield, no requirement on column chromatography and simplicity and safety in operation. The spiro 4-hydropyrazole compound obtained by the invention is an important chemical and pharmaceutical intermediate, and some compounds with specific structures also have very high biological activities, for example MKN-0677 and widely used as cancer inhibitors in the pharmaceutical field. In addition, thespiro 4-hydropyrazole compound can be used as a good monodentate ligand to form a metal complex with metal, and expected to be used in asymmetric catalysis. The method has the reaction formula as shown in the description.