Abstract: Aluminum finned ferromagnetic tubes in service are difficult to be inspect because conventional inspection techniques cannot be applied on. Two uncommon inspection techniques of MFL(Magnetic Flux Leakage) inspection and IRIS(Internal Rotary Inspection System) were tried to find the applicable inspection technique of aluminum finned ferromagnetic tubes. The applicability, advantage and disadvantage of the two techniques were found through the test of sample tubes with man-made defects respectively. And the applicable inspection technique of aluminum finned ferromagnetic tubes in service was concluded finally, by the analysis of the test and the characteristics of MFL and IRIS inspection techniques.