The invention relates to the technical field of dangerous rock mass monitoring and early warning, in particular to a dangerous rock mass acousto-optic combined intelligent monitoring and early warning method. The method comprises the steps of S1, selecting an object, specifically, selecting a dangerous rock mass below which a threatened object exists; S2, installing instruments, specifically, installing an alarm instrument on a stable mountain body on the inner side or the side of the dangerous rock mass, wherein the alarm instrument comprises a control module, and installing a monitoring instrument on the dangerous rock mass or between the dangerous rock mass and the mountain body; and S3, performing initial data acquisition, specifically, acquiring data of the size, shape, height, inclination direction, inclination angle, displacement, crack width, landform conditions of the dangerous rock mass and distribution of threatened object through two modes, namely, the monitoring instrument and manual observation, and inputting the manually acquired data into the monitoring instrument. According to the technical scheme, the dangerous rock mass is monitored in real time, meanwhile, when the dangerous rock mass collapses, a sound-light alarm signal is sent out at the first time, a safe escape path is pointed out to threatened people, and the personal safety of the people is ensured.