The invention relates to an ensemble empirical mode decomposition (EEMD) and approximate entropy combined steel tube damage monitoring method, and aims to accurately monitor the inside, the outside and the end of a steel tube in all directions, accurately judge whether the steel tube is qualified or not and show the damage degree of the unqualified steel tube. The device comprises a detection acquisition unit, a signal processing unit, a judging unit, an output display unit and an alarm unit. A monitoring method comprises the following steps: at first, detecting the inside, the outside and the end of the steel tube by using the detection acquisition unit with a multi-sensor in all directions and acquiring damage signals; then, processing the required damage signal by using the signal processing unit according to the detection and acquisition result, sending the processed signal to a damage judgment unit, and analyzing the processed signal and converting the processed signal into a specific damage grade signal by using the damage judgment unit; finally, displaying an output signal by using the output display unit and the alarm unit. According to the EEMD and approximate entropy combined steel tube damage monitoring method, fusion detection is carried out by using the multi-sensor, and accurate testing steps are planned, so that the damage of the steel tube can be effectively monitored.