Points of zero charge (PZC) of goethite as control and several ores of manganese oxides were determined with different methods,e.g.potentiometric titration (PT),rapid potentiometric titration (RPT),salt titration (ST) and the improved salt titration (IST).Results showed PZC of birnessite,cryptomelane,todorokite was 1.18,1.98 and 3.98 respectively with PT and 1.75,2.10 and 3.50 respectively with RPT.With ST there was no point of intersection of pH of manganese oxides and x-axis.However,when 0.5 ml 2 mol L^-1 KCl was added into the solution and its equilibrium duration was set at 24 h,PZCs of the manganese oxides were determined to be 0.98,1.72 and 3.31,respectively.The PZCs of goethite obtained with the PT and RPT methods were both 8.00 showing no difference between the two methods,and with the ST and IST methods were 8.31 and 8.41 respectively,showing a minor difference.After the ST method was improved,it could be used to determine PZC of manganese oxides.This method was reliable,simple and convenient compared with the PT and RPT methods.