Abstract: A vehicle deceleration warning apparatus is activated immediately when a driver of the vehicle intends to decelerate. The vehicle deceleration warning apparatus includes an ignition monitoring module, a first microprocessor module, a wireless transmitting module, a wireless receiving module, a second microprocessor module, and a display driving module. The ignition monitoring module receives an ignition signal and delivers it to the first microprocessor module. The first microprocessor module performs a calculation by adopting the ignition signal to generate a control signal. Then, the control signal is transmitted to the second microprocessor module wireless transmission. Finally, the second microprocessor module controls the display driving module to generate a display driving signal to a display device, such as a brake light and a warning lamp, so as to generate a warning light representing deceleration of the vehicle.