The invention discloses a method for synthesizing 2'-spiro-substituted ternary carbocyclic nucleoside, and belongs to the technical field of organic chemistry. The method for synthesizing the 2'-spiro-substituted ternary carbocyclic nucleoside comprises the steps of using alpha-pyrimidine-substituted acrylate and alpha-chloronaphthenone as raw materials, and synthesizing the spiro nucleoside novelin structure through cyclopropyl cyclization reaction started by Michael reaction. According to the method for synthesizing the 2'-spiro-substituted ternary carbocyclic nucleoside, the adopted raw materials are simple and easy to obtain, in the synthesis process, and the defects of a wide variety of steps, a low yield and poor universality of a former method are overcome. The yield of the spiro pyrimidine nucleoside synthesized through the method is up to 84%, and products are rich in structure.