A wearable ultrasonic therapeutic device controlled by a mobile electronic device is provided, which includes a mobile device, at least one ultrasonic probe module and a strap. The mobile device has a mobile device control interface for setting ultrasonic parameters and displaying an echo wave through a specific software interface of the mobile device. The ultrasonic probe module includes at least one ultrasonic transducer and a control circuit corresponding thereto. The ultrasonic transducer generates and receives an ultrasonic wave. The control circuit has the functions of generating/receiving signals, phase regulation, power amplification and matching. One end of the ultrasonic probe module is electrically connected to the mobile device and the other end of the ultrasonic probe module is connected to the strap.