In order to analyze the problem that the predicted value of the acoustic emission gray model GM(1,1) is established by the traditional gray theory for the number of acoustic emission events compared with the experimental value and the prediction accuracy is not high, the replacement rate of the recycled coarse aggregate is 30%. The acoustic emission phenomenon of recycled concrete beams during bending failure was improved by introducing the reduction factor k, and the expression of the reduction factor in the whole process of beam failure was given. By comparing with the experimental results, the predicted and experimental values of the GM(1,1) grey model are compared. The final results show that the reduction coefficient k has a good nonlinear relationship with the time t, which is 0.5k at the starting point and the ending point respectively. And 3k. According to the above characteristics, the corrected gray model has a higher precision than the traditional model. The model is used to analyze the acoustic emission parameters during the stress process of the material, and then the discrimination and prediction of the instability of the recycled concrete beam are realized. It provides a reference for predicting material damage in the future.