A braking system having an electromechanical braking function may include a compound caliper device including a motor and configured to press a pair of brake pads against a brake disk, a hydraulic pressure producer including a master hydraulic line receiving oil from a master cylinder, a master valve configured to open and close the master hydraulic line, a caliper hydraulic line connected to the compound caliper device, and a hydraulic pump configured to increase hydraulic pressure supplied to the compound caliper device, and a brake controller to control the motor and the hydraulic pressure producer, in which the brake controller is configured to close the master valve and decrease clamping force of the brake pads applied by the motor when a conversion condition for converting a parking brake stage into a primary brake stage is satisfied.