An interlocking control device for a multiple-unit safety circuit, comprising: a protective grounding switch control branch which comprises: a pantograph rising pneumatic circuit cut-off valve (J1), a protective grounding switch turn-off pneumatic circuit cut-off valve (J2) and a protective grounding switch turn-off solenoid valve (Y1) which are connected in series; wherein keys for a high-voltage equipment cabinet and an external power supply cabinet are located in a key box; a cover of the key box is mechanically locked by means of a pantograph rising pneumatic circuit cut-off valve (J1) and a protective grounding switch turn-off pneumatic circuit cut-off valve (J2); when high-voltage equipment of a multiple-unit train is under inspection and maintenance or is powered by an external power supply, a protective grounding switch is turned on, a cock of the pantograph rising pneumatic circuit cut-off valve (J1) and a cock of the protective grounding switch turn-off pneumatic circuit cut-off valve (J2) are rotated to open the cover of the key box; simultaneously, the protective grounding switch control branch is disconnected, and the protective grounding switch turn-off solenoid valve (Y1) connected in series in the protective grounding switch control branch is powered off to maintain the protective grounding switch in an on state; characterized by a first pantograph interlocking control branch which comprises: a normally-closed contact (D) of the protective grounding switch and a coil (C) of a pantograph rising relay which are connected in series, wherein the normally-closed contact (D) of the protective grounding switch is opened and the coil (C) of the pantograph rising relay is powered off when the protective grounding switch is turned on, such that a pantograph is unable to rise. a protective grounding switch control branch which comprises: a pantograph rising pneumatic circuit cut-off valve (J1), a protective grounding switch turn-off pneumatic circuit cut-off valve (J2) and a protective grounding switch turn-off solenoid valve (Y1) which are connected in series; wherein keys for a high-voltage equipment cabinet and an external power supply cabinet are located in a key box; a cover of the key box is mechanically locked by means of a pantograph rising pneumatic circuit cut-off valve (J1) and a protective grounding switch turn-off pneumatic circuit cut-off valve (J2); when high-voltage equipment of a multiple-unit train is under inspection and maintenance or is powered by an external power supply, a protective grounding switch is turned on, a cock of the pantograph rising pneumatic circuit cut-off valve (J1) and a cock of the protective grounding switch turn-off pneumatic circuit cut-off valve (J2) are rotated to open the cover of the key box; simultaneously, the protective grounding switch control branch is disconnected, and the protective grounding switch turn-off solenoid valve (Y1) connected in series in the protective grounding switch control branch is powered off to maintain the protective grounding switch in an on state; characterized by a first pantograph interlocking control branch which comprises: a normally-closed contact (D) of the protective grounding switch and a coil (C) of a pantograph rising relay which are connected in series, wherein the normally-closed contact (D) of the protective grounding switch is opened and the coil (C) of the pantograph rising relay is powered off when the protective grounding switch is turned on, such that a pantograph is unable to rise. <EOS>