The invention discloses a preparation method of a silver nano particle loaded metal organic framework complex catalyst. The preparation method of the silver nano particle loaded metal organic framework complex catalyst by adopting an impregnation method comprises the following steps: firstly, synthesizing a metal organic framework complex MIL-101; and then, preparing the silver nano particle loaded metal organic framework complex catalyst Ag@MIL-101, wherein the silver nano particle loaded metal organic framework complex catalyst is used for converting CO2 into phenylpropiolic acid via the reaction of CO2 and phenylacetylene under a mild reaction condition. The preparation method of the silver nano particle loaded metal organic framework complex catalyst, which is provided by the invention, has the advantages that the catalyst can adsorb a CO2 molecule so as to improve the solubility of the CO2 molecule in a solvent, thereby improving the reaction velocity; the catalyst is simple to prepare, belongs to a heterogenous catalyst, avoids the difficulty that a homogeneous catalyst is difficult to separate, and has an obvious technical effect.