A training method and a training device for a neural network based on memristors are provided. The neural network includes a plurality of neuron layers connected one by one and weight parameters between the plurality of neuron layers, and the training method includes: training the weight parameters of the neural network, and programming a memristor array based on the weight parameters after being trained to write the weight parameters after being trained into the memristor array; and updating a critical layer or several critical layers of the weight parameters of the neural network by adjusting conductance values of at least part of memristors of the memristor array.