Disclosed are a parking brake system of an EMB used in combination with a hydraulic device, and a parking brake control method for an EMB. The parking brake system of an EMB according to an exemplary embodiment of the present invention includes: a pedal unit which has a configuration in which a pedal simulator and a master cylinder are coupled; electromechanical brakes (EMBs) each of which has a hydraulic piston device; first hydraulic lines which are connected so as to supply hydraulic pressure from the master cylinder to the hydraulic piston devices of the EMBs; first solenoid valves which are provided to change a communication state of the first hydraulic lines; second hydraulic lines which are extended between the first solenoid valves and the EMBs, and connected to a reservoir; and second solenoid valves which are provided to change a communication state of the second hydraulic lines.