Automatic removable cover that ventilates of transformer substation, including the several apron, install the controller on the apron, set up the ventilation hole on the apron, set up the baffle on the ventilation hole, set up the boss on the apron, the one end of baffle is articulated with the apron, the other end of baffle is located the boss, the baffle can be with the hole closure of ventilating, cover plate top surface installs a humidity transducer, apron bottom surface the 2nd humidity transducer of installation and fan, the fan is located ventilation hole lower part, a humidity transducer, the 2nd humidity transducer and fan are connected with the controller respectively. The utility model discloses in, through set up the ventilation hole on the apron to set up the fan in ventilation hole lower part, ventilation hole upper portion hinge baffles, and measure the humidity inside and outside the ditch by humidity transducer according to the humidity data, starts the fan by the controller, and the baffle on the hole upper portion that will ventilate blows afloat, and moisture in the discharge gutter, prevents that the cable pit internals from receiving the corrosion, avoids the cable reduced insulation.