Abstract: Based on the locating theory of acoustic emission in-service inspection for tank bottom, technical plan and implementing steps of the inspection are presented, With parameter and wave analyzing method combined, acoustic emission signal acquired is processed, Through filtering, clustering and analyzing based on parameter correlative diagram, the noise signal is filtered, Based on available events from all channels per unit time and average energy of the events, grade evaluation is carried out to obtain the corrosion information of tank bottom, which is a fundamental for presented maintenance advice, In order to evaluate performance of the method, an in-service field inspection on 5 000 m³ oil products tank is made, then a traditional MFL technology is followed up, Comparative result shows that there is consistency in corrosion localizing accuracy in the two inspection methods, It demonstrates the feasibility for in-service inspection technology used in tank bottom.