The utility model discloses a multi-mode-mounted electric fire hazard monitoring detector. The detector comprises a residual current transformer for detecting leakage current and a detector in signal connection with the residual current transformer. The detector comprises a casing; a clamping groove is formed on the back of the casing; and screw hole seats are fixed at the upper end and the lower end of the casing. The utility model has the advantage of multiple mounting modes: (1) clamping groove mode, convenient for being mounted on a distribution cabinet switch guide rail, (2) screw hole mode, convenient for being fixed on a box body, (3) hang mode, realizing integrated mounting of the current transformer and the detector through hanging the current transformer onto the detector. The three mounting modes bring convenience for a user to conveniently, flexibly and effectively mount the detector in a newly-built building or an existing building for fire fighting modification.