An ejection type automobile safety warning signboard and an ejection system thereof. The warning signboard has a polyhedral structure (1a) used for inhibiting rolling in a free state and may be bound into a tubular storage state (1b) under the action of an external force and be automatically released into the polyhedral structure (1a) after the external force is removed. The surface of the polyhedral structure (1a) is provided with a warning marker (101). The ejection system comprises: a warning signboard; a discharge tube (2) having an inner cavity; a pressure tank (3) communicating with the end of the discharge tube (2); a solenoid valve (4) arranged between the discharge tube (2) and the pressure tank (3); a controller (5) electrically connected to the solenoid valve (4); and a piston (6) provided in the discharge tube (2). When an emergency occurs during the travel course of a motor vehicle, the driver may start the ejection system while braking, so that a safety warning signboard pops up and stays near the position where the braking starts. The position of the safety warning signboard has a certain distance from the stop position of the motor vehicle, so that the driver is not required to take out the warning signboard and walk such distance after stopping the vehicle, which may effectively warn the vehicle behind in time, thereby reducing the probability of a rear-end collision.