A fabrication method of tricyclodiester with bicyclopentaclene equalization phase catalyzing hydrogen ester base is presented in this invention. Palladium-phosphorus-acid is calatysis system, bicyclopentaclene, carbon monoxide and alcohol or methyl alcohol are reacted to generate over 80% tricyclodiester, other is tricyclic olefin monoester. Total selectivity is approximately 100%. As compared with DE3,308,882 patent, the reaction pressure is decreased from 300 bar to 60 bar, the productivity of tricyclodiester is higher.