The invention discloses a ping-pang control-based single-back direct current large signal modulation controller and a control method thereof. The ping-pang control-based single-back direct current large signal modulation controller comprises a sampling controller (S1), a differential controller (S2), a power controller (S3), a power limiter (S4) and a power converter (S5). The ping-pang control-based single-back direct current large signal modulation controller has the advantages that operation states of an alternating current and direct current power transmission system can be monitored in real time in an online way, the system stable conditions is rapidly judged, a direct current large signal modulation strategy is formulated according to the stability degree when a serious alternating current failure or other single-back direct current bipolar interlocking occurs, a power balance relationship between areas is effectively controlled during a generator group swinging process by rapid emergency modulation of the direct current power in real time, power angle swinging is restrained and the stability limit is improved.