The invention provides a safety detection device for transformers. The safety detection device comprises a main control unit (1), an electric leakage detection module (2), an electric leakage acquisition module (3), a power-off protection module (4), an alarm module (5), a display module (6) and a power module (7). The main control unit (1) is connected with the electric leakage detection module (2), the electric leakage acquisition module (3), the power-off protection module (4), the alarm module (5) and the display module (6). The electric leakage detection module (2) is connected with the electric leakage acquisition module (3). The power module (7) is connected with other modules through wires.