The invention relates to a partial discharging detecting device of a switch cabinet. The partial discharging detecting device comprises an ultrahigh frequency sensor, an ultrasonic sensor, a high frequency current transformer and a transient earth voltage (TEV) sensor which are used in the field of sensors for measuring partial discharging. The partial discharging detecting device collects data of various sensors through a monitoring system so as to achieve measurement of partial discharge capacity inside the switch cabinet conveniently and effectively and conduct precise locating of partial discharging positions and provides data monitoring proof for insulation performance estimation of the switch cabinet.