The kinetics regarding to the pressure leaching of pyrite ores at elevated temperature and pressure was investigated. The leaching rates were proportional to the oxygen partial pressure, temperatures and the specific surface area of the sample, and were independent of the concentration of the sulfuric acid. The activation energy of the domestic pyrite ores for pressure leaching was 10.1 kcal. per mol. Pyrite ores were completely decomposed into free sulfur and ferrous or ferric sulfate when leaching was carried out for 4 hours at 115℃ under 20 atom, of oxygen partial pressure in dilute sulfuric acid solutions. Some electrolytic effect was briefly tested by applying anodic current during the pressure leaching at a means of accelerating the rate of leaching. It was proved that the combination method of acid leaching and anodic dissolution was effective for pressure leaching of pyrite ores.