Uniaxial compression test and acoustic emission test were carried out on tuff with double round holes of different rock bridge lengths to obtain the acoustic emission parameters of rock deformation and failure process. The influence of rock bridge length on acoustic emission response characteristics was studied, and the early warning precursor information was analyzed based on acoustic emission characteristic parameters. The results show that the acoustic emission parameters change periodically with time, and there are obvious abnormal response characteristics before rock failure. AE energy changes from group earthquake type to solitary earthquake type with the increase of rock bridge length. AE ringing count has experienced quiet period, active period and sudden increase area. AE RA/AF value is sensitive to local small crack propagation. AE b value has experienced rising period, fluctuation period and falling period with time, and the overall trend is decreasing. Each parameter of AE has the precursor of rock failure. The AE cumulative energy, AE cumulative ring count, AE cumulative RA/AF value sudden increase point and the lowest point of AE b value are taken as the’ critical failure precursor point’ D. The early warning time series is: AE cumulative RA/AF value > AE cumulative ring count > AE cumulative energy > AE b value.