Abstract: For typical signals obtained by the tank bottom leakage detection process, such as scratching, lap joint, corrosion and butt welding, based on the practical experience and graphic display, analysis method of using FloormapVS2i software and the counter measures for deleting interference data and adjusting the display response threshold were presented to improve the accuracy of the result of magnetic flux leakage testing. The above mentioned measures can provide the reference for the magnetic flux leakage detection of atmospheric storage tank.