The invention provides a method for determining a water-flowing fractured zone of an overlaying rock stratum to be monitored. According to the invention, a monitoring profile is selected at the position of an overlaying rock stratum to be monitored of a coal mine planning exploration area, total change values in resistivity of all strata in the monitoring profile are acquired in the process that the position of the monitoring profile changes from a planning exploration area into a mined-out area, that is, in the whole process that the overlaying rock stratum is damaged, and thus an average value of the total change values in resistivity of all strata in the monitoring profile is obtained, so that the water-flowing fractured zone of the overlaying rock stratum to which the monitoring profile belongs according to the total changes values in resistivity of all strata in the monitoring profile, the average value of the total change values in resistivity of all strata in the monitoring profile, position information of all strata in the monitoring profile and the depth of the overlaying rock stratum to be monitored, thereby providing an accurate basis for a coal mine to prevent gas and underground water.