A parking brake control method for an electromechanical brake system of an urban rail vehicle includes an operation instruction mechanism, a brake control mechanism, an electromechanical actuating mechanism and an auxiliary mechanism. The operation instruction mechanism outputs a control signal to the brake control mechanism to drive the action of the electromechanical actuating mechanism so as to achieve braking application and relief of the vehicle. The auxiliary mechanism is used for a redundant power supply system of a brake system. The auxiliary mechanism further includes a zero-speed state monitoring mechanism for monitoring a zero-speed state of the vehicle and an energy storage battery mechanism for providing a backup power supply. The parking brake control method enables an urban rail vehicle using an electromechanical brake system to achieve brake application and relief in a parked state and achieve brake application and relief in a dormant state of the urban rail vehicle.