Abstract: This paper introduces a potentiodynamic polarization measurement apparatus in which one of the parts is a potentiostat having no medium resistance compensator.A new type of salt bridge is described.Potentiodynamic measurement procedure and test conditions of polarization curve for steel in the soil paste are given.Using Type 16 manganese steel and Type 45 carbon steel as samples and Ma Gan soil (yellow brown earth) and two marine solonchaks as test media,polarization curves recorded by potentiodynamic measurement under different conditions are described.Test results show that the method has considerable reliability and better reproducibility.