The invention belongs to the technical field of nondestructive testing, in particular to a self-adaptive NNT cancellation method for ultrasonic eddy current signals. The method comprises the followingsteps of carrying out zero-mean processing and noise reduction on the cancellation signal H and the cancelled signal R; constructing an adaptive neural network; obtaining an output signal, subtracting the de-noised value output signal to obtain a cancellation signal in the ultrasonic eddy current signal, and in the ultrasonic eddy current signal cancellation method, based on a self-adaptive cancellation method of a neural network technology, effectively inhibiting strong clutters such as initial waves and bottom waves, and ensuring that the extracted signal does not have abnormal fluctuationand mirroring phenomena, so that the defect detection accuracy is high; the algorithm is steady and reliable and has no ill-conditioned problem; the processing time is short, the real-time performanceis high, and online and offline real-time detection is facilitated.