Manganese (hydrous) oxides are highly active oxides in soil and sediment. They possess variable negative charge and often exist as coatings or fine particles on the surfaces of soil and sediment, controlling the concentration of trace metals in soil, sedimentand natural water system by adsorption or redox. Mn oxides also act as environmental materials, which were used as adsorbents, heterogeneous catalysts and molecular sieves. Point of Zero Charge (PZC) is a fundamental parameter of surface charge of colloids. Several methods have been developed for determination of the point of zero charge. The Salt Titration (ST) method was proposed by Uehara and Gillman in 1980 and successfully and widely applied to determine the PZC of soil, mineral and colloid. Compared with the Potentiometric Titration (PT) method, the operation of ST method was simple, required a small quantity of sample and its result was accurate. However, little information was available on using ST method to measure the PZC of Mn oxides. The objectives of this research were to determine the PZC of birnessite, cryptomelane, todorokite and goethite using an Improved ST method (IST) and compare the obtained results using different PZC determination methods. The PT method yielded PZC of 1.18, 1.98 and 3.98 for birnessite, cryptomelane and todorokite, while the rapid potentiometric titration (RPT) method of 1.75, 2.10 and 3.50, respectively. There was no intersection between ÄpH and x- axis for the ST method, even when the types and concentrations of the added electrolytes changed. However, when 0.5 ml of 2 mol/L KCl solution was added and reacted for 24 h, the PZCs of birnessite, cryptomelane and todorokite were 0.98, 1.72 and 3.31, respectively. An improved ST method (IST) was proposed and results showed that it could be used to determine the PZC of manganese oxides. The PZC values of goethite obtained by PT and RPT methods showed no differences of 8.00, and that by ST and IST methods showed minor differences of 8.31 and 8.41, respectively. Compared with PT and RPT methods, the IST was more reliable, simple and convenient. Key Words: Point of zero charge, Potentiometric titration, Salt titration, Manganese oxides, Method improvement.