This paper introduces the elementary principle of the high density resistivity
imaging method which springs up in the field of hydrology, engineering and
environmental geophysical prospecting in recent year. According to the characteristics of
the diseases of the railway bed, the study and application of the high density resistivity
imaging technique have been carried out and a new measurement scheme and data
processing-image software system are developed. By comparing the results of the finite
element numerical simulation to image formation and the field measure of the typical
diseases of railway bed, it shows that the new technique is accurate, effective and
convenient for detecting diseases of railway bed.