Both immobilization of Ag nanoparticles (AgNPs) of very small size on hierarchical porosity supports and carboxylative cyclization of propargyl alcohols with CO2 under ambient conditions are very interesting. In this work, we synthesized AgNPs supported on sulfonated macroreticular resin (SMR) with hierarchical pores in water/alcohol solutions. It was shown that the size of the AgNPs on the SMR could be tailored easily by altering the synthetic solutions, and very small AgNPs with narrow size distribution (1-3 nm) could be obtained in water/methanol solution. It was found that the AgNPs/SMR with small AgNPs was highly efficient and an easily recyclable catalyst for the synthesis of α-alkylidene cyclic carbonates by carboxylative cyclization of propargyl alcohols with CO2 at ambient pressure and temperature, which was the first work to use metal nanoparticles as the catalysts for the reaction.