Abstract: The acoustic emission (AE) characteristics of sandstone and filling sandstone composite specimens under uniaxial compression were studied.The AE counts and dominant frequency characteristics were discussed.The differences of AE signals collected from sandstone side and filling side in composite specimens were compared.At the same time,BP neural network was used to identify the AE signal types of composite specimens.The law of proportion and time-stress of different types of AE signals in the failure process are analyzed.The results show that the average uniaxial compressive strength of composite specimens is only 38.85% of sandstone specimens.The number of AE counts of composite specimens are less than sandstone specimens in the failure process.The AE counts on the sandstone side of the composite specimens increased significantly before the peak stress.The proportion of AE signals of sandstone type in the composite specimens gradually decreased before failure,while the proportion of filling type signals gradually increased.This phenomenon can be used as a precursory feature of the failure of composite specimens.