Abstract: A great deal of practices indicated that the tank bottom is the emphasis and difficulty of inspection as against the tank deck and shell, and it is the serious corrosion on below surface of tank bottom that forms the main causes leading to the descending strength and moreover perforation and leakage of tank bottom, so a significant task of inspection on tank bottom is to find out corrosive status on below surface of tank bottom in detail. Present paper introduced in detail the out-service inspection and in-service inspection technologies on atmospheric vertical storage tank, mainly introduced the characteristic and product models of the various inspection technology. Emphasis was put on the characteristics, using status and application circumstances of acoustic emission testing, magnetic flux leakage testing and ultrasonic testing. By the comparison of their merit and demerit of the various inspection technologies a comprehensive inspection and evaluation flow on tank bottom was put forward, providing useful references for correct decision-making and scientific examining and repairing.