The invention discloses an electric automobile and a high-voltage protection device thereof. The device comprises a high-voltage power distribution box, at least one electric arc sensor, controllable switches and a control unit. The high-voltage power distribution box is provided with a plurality of branches. The multiple branches are connected with a power battery and at least one high-voltage load correspondingly. The electric arc sensors are arranged in the multiple branches. Each electric arc sensor is used for generating an electric arc fault signal when the corresponding branch is in an electric arc fault. The controllable switches are arranged corresponding to the electric arc sensors. The control unit is connected with the at least one electric arc sensor and the controllable switches and used for controlling the controllable switches according to the electric arc fault signals after receiving the electric arc fault signals so as to switch off the corresponding branches. Accordingly, the electric arc faults can be detected effectively, and the corresponding branches can be switched off timely when in electric faults, the safety problem, caused by the electric arc faults, of the branches is prevented, and the safety and the reliability of the vehicle are promoted.