Abstract: A series of Pd/C catalysts for hydropurification of terephthalic acid were prepared using sol-gel process. The effect of reduction temperature on the microstructure and activity of the catalysts were investigated by means of SEM, TEM, EDS, physisorption, chemisorption and HPLC. The results show that the activity and dispersion of Pd sharply decreases with the increase of reduction temperature. The conversion ratio of 4-CBA is close to 100% at reduction temperature of 10℃ and the dispersion of Pd also reaches the highest. The Pd particles at this condition are fine and equally distributed with average size of about 6.45 nm. However, a lot of larger particles with size of 15-20 nm gather at the surface at reduction temperature of 30℃. The amount of Pd on the catalyst surface reduced at 30℃ is about five times the amounts of Pd on the surface reduced at 10℃. Higher temperature generally causes the breaking of hydrogen bond between polyoxyethylene group and water, leading to a great reduction of solubilization capacity, which further results in the growth of Pd grain and the decrease of activity of Pd/C catalysts because of increased collision probability of Pd colloids.