The invention relates to the technical field of checking of protective trip outlets in transformer substation protection screens, in particular to a self-holding protective trip outlet checking device. The device comprises a box body, a power switch installed on the box body, a power module arranged in the box body and a plurality of trip outlet test loops connected in parallel, wherein each tripoutlet test loop comprises a relay, a current-limiting resistor and a light-emitting diode, a positive electrode of the power module is electrically connected to the power switch, the power switch iselectrically connected to a relay coil, the relay coil, a first normally open contact of the relay and a second normally open contact of the relay are electrically connected in sequence, the second normally open contact is connected to the current-limiting resistor, the current-limiting resistor is electrically connected to the light-emitting diode, and a protective outlet node is arranged betweenthe relay coil and a negative electrode of the power supply. The device is reasonable and compact in structure and convenient to use, and the trip outlet test loops are connected in parallel, so thata plurality of trip outlets can be tested at the same time, and thus the protective outlet checking time is effectively shortened, and the working efficiency is improved.