After utilizing an improved method for adding a non-precious promoter to the precious Pd/C catalyst during hydrogenation of benzoic acid, a new understanding concing regeneration of deactivated Pd/C catalyst has been obtained, and an improved process has emerged. The improved process can avoid the conventional technical shortcomings related with hydrogenation of benzoic acid such as the quick decline of catalyst activity in a relatively short period of time and low palladium recovery from the spent catalyst. Furthermore, according to this process, cyclohexane carboxylic acid (CCA) can be produced favorably in a commercial scale at a high selectivity and product yield with a extended catalyst life.