The invention discloses a neural 
network method for diagnosing analog circuit failures which is based on a 
particle swarm algorithm, and comprises the following steps: imposing an actuating 
signal to an analog circuit to be tested, measuring an actuating response 
signal in the testing nodes of the circuit, extracting the candidate 
signal of failure characteristics by implementing 
noise elimination and then 
wavelet packet transformation on the measured actuating response signal, extracting the failure characteristics information by further implementing orthogonal 
principal component analysis and normalization 
processing on the candidate signal of failure characteristics, and sending the failure characteristics information as samples to the neural network for implementing classification. The method adopts the 
particle swarm algorithm instead of a 
gradient descent method in traditional BP algorithms, thus leading the 
improved algorithm to be characterized in that the 
algorithm avoids the local minimum problem and has better generalization performance. The BP neural 
network method for diagnosing the analog circuit failures which is optimized on the basis of particle swarm can obviously reduce iteration times in the 
algorithm, improve the precision of 
network convergence, and improve diagnosis speed and precision.