Abstract: The present summary is about the problems encountered during the magnetic flux leaking(MFL) inspecting for many storage tanks. Six issues were discussed in brief including the controlling of the scanning coverage percentage, the directionality effect of defects, the effect of residual magnetism, the defect positioning on single floor, the rechecking cases using ultrasonic method and the effect of surface condition, etc. Some empirical recommendations and conclusions were proposed to promote the MFL inspection work of bottom floor corrosion.