The invention discloses an early warning system and method of an operating vehicle of high-voltage electrical equipment. The method comprises steps of carrying out real-time positioning on the position of a mechanical arm top end of the operating vehicle; processing position positioning information of the mechanical arm top end of the operating vehicle to obtain the altitude vertical height of the mechanical arm top end of the operating vehicle, and the horizontal distance, the angle, the speed and the accelerated speed relative to a high-voltage electrified body; carrying out real-time positioning on the position of an operating vehicle operation chamber; according to the position positioning information of the mechanical arm top end of the operating vehicle and the position positioning information of the operating vehicle operation chamber, obtaining information of the relative vertical height, the horizontal distance, the angle, the speed and the accelerated speed between the mechanical arm top end of the operating vehicle and the high-voltage electrified body; and according to a preset critical value, judging whether the current values exceed the critical value, and if yes, sending alarming control information. According to the invention, the distance between the operating vehicle and the high-voltage electrified body can be precisely detected; the alarming result is quite reliable; and the system and the method are suitable for electric power systems.