The invention discloses an ultrasonic detection defect qualitative recognition method based on a neural network, and the method comprises the steps: carrying out the preprocessing of a damage signal through employing a wavelet packet threshold noise reduction algorithm in a wavelet analysis algorithm, reserving a useful signal in a first intrinsic mode component as much as possible, and carrying out the mode decomposition of the signal through employing a complementary set empirical mode decomposition algorithm; carrying out soft threshold noise reduction and rigrsure noise reduction, finally, carrying out superposition reconstruction on two parts of processed intrinsic mode components to obtain a final signal, and secondly, extracting feature vectors of different damage conditions to form a learning sample of a multivariable interpolation radial basis function. According to the method, noise reduction processing can be carried out on the collected signals, the convergence speed is high, the method is simple and effective, the radial basis function neural network after learning training has the capacity of ultrasonic detection defect qualitative recognition, device damage and the damage degree can be accurately recognized, and the damage positioning can be achieved.