The utility model discloses an intelligent detection device for a direct current power supply system of a transformer substation. The intelligent detection device comprises a high-frequency rectifier circuit (1), wherein the high-frequency rectifier circuit (1) is respectively connected with a high-frequency rectifier circuit direct current output terminal (2), a polarity detection circuit (3), a looped network and a parasitic detection loop (4), and the direct current output terminal (2) is respectively connected with the polarity detection circuit (3), the looped network and the parasitic detection loop (4). The intelligent detection device is safe and rapid, and is rapid and accurate in judgment; and the work of a direct current system is facilitated and simplified.