Abstract: The present disclosure discloses a trailer braking control method and system based on an electric brake controller. A lateral displacement and speed of a vehicle are acquired first; whether the vehicle has Death Wobble and a degree of the Death Wobble are then determined according to the lateral displacement; if there is Death Wobble, a driving state of the vehicle is determined according to the speed; and finally, a set voltage is added based on a set output voltage according to the degree of the Death Wobble and the driving state, so as to brake the vehicle. The present disclosure avoids setting of a weight ratio in the prior art to prevent the phenomenon of Death Wobble, and can identify and prevent the phenomenon of Death Wobble of a trailer, thereby avoiding an overturning accident and ensuring the personal safety and the integrity of a vehicle.