A monitoring and forewarning method for coal-rock dynamic disasters based on an electromagnetic radiation and an earth-sound monitoring includes the following steps: (1) calculating the weighted average value of research parameter P(t) during a time period according to the monitoring data collected by the electromagnetic radiation and the earth-sound monitoring system in real time; (2) calculating D(t), the deviation value of P(t); (3) calculating |D(t)| as the deviation threshold value, the average value of |D(t)| during period of normal mining of the working surface; (4) calculating DS, the number of times that D(t) is greater than |D(t)| in one day; (5) normalizing DS to obtain the monitoring and forewarning index ε; (6) forewarning the hazard state of dynamic disaster of the working surface in real time according to ε and forewarning method, determining hazard level.