Abstract: The mixtures of cis/trans-4-(5′-propyl-tetrahydropyran-2′-yl)-cyclohexanecarboxylic acid(3PyHA) were synthesized with trans-4-(5′-propyl-tetrahydropyran-2′-yl)-benzoic acid (3PyPA) by catalytic hydrogenation. The results of hydrogenation condition experiments showed the reaction effect was best with Ru/C as catalyst, NaOH solution as reaction medium, when the reaction temperature was 75～85 ℃ and hydrogenation pressure was 3.5 MPa. More than 99.5% purity of trans-4-(5′-propyl-tetrahydropyran-2′-yl)-cyclohexanecarboxylic acid(3PyHA) can be obtained with isomerization reaction of high temperature and recrystallization with toluene and ethanol.