A braking ratio device for a remote control model is composed of a suspending arm and a ratio device. The suspending arm is fixed with a shaft of a servo motor, having a controlled member formed at its one side and a driving member extended out from one end of the controlled member. The ratio device is provided with a pivotal base pivotally mounted on the controlled member, and a ratio base connected with the pivotal base to be able to move axially. A front brake connecting rod and a rear brake connecting rod are respectively inserted through two sides of the ratio base, to alter the distance between the front brake connecting rod and a front braking set, and also the distance between the rear brake connecting rod and a rear braking set, for creating a time difference of braking for the front and the rear braking sets.