The invention discloses an image classification method based on random calculation Bayesian neural network error injection. The method comprises the following steps: S1, scaling input data, weight parameters and bias parameters; S2, converting the scaled floating point input data, the scaled floating point weight parameter and the scaled floating point bias parameter into a random bit stream form through a forward conversion circuit; S3, building a random calculation neuron structure of the Bayesian neural network; S4, calculating the scaling of each neuron node, and performing forward reasoning; S5, converting the output bit stream into a floating point form, and obtaining an output result of single reasoning; and S6, repeating the steps S4-S5, taking a mean value, and taking the mean value as a classification result. According to the image classification method based on Bayesian neural network error injection, inherent noise characteristics are calculated randomly, an additional error injection circuit does not need to be introduced, and unification of calculation and error injection in the Bayesian neural network reasoning process is achieved.