Abstract: The rock strength involves the interaction and inter-coupling of many influencing factors. The conventional methodis unable to evaluate the interaction relationship among the influencing factorsaccurately. Therefore according to previous scholars' achievements and practical experience, the essay introducesthe interactive matrix of Rock Engineering System(RES) theory, and applies the increscent coefficient ofhyperbolic tangent function asthe BP network coding way of activation function. The thesis also presents the predicted model ofinteractive matrix of BP network of rock strength based on RES and involves network training. The final result shows that applying theanalytical thought of REstheoretical system on the basis of the construction of interactive matrix and with the improved BP networknot only predict the rock strengthquickly, but also improve the prediction accuracy. This research not only provides a new idea for rock strength prediction, but also provides a new way forrock mass engineering evaluation.