A wearable ultrasonic device constantly emitting waves attached with a readout display device includes a frame defining a space, an ultrasonic sensor, and a display panel received in the space. The ultrasonic sensor monitors a user's health. The display panel is positioned on the ultrasonic sensor. The ultrasonic sensor includes a signal transmitting layer configured to emit ultrasonic waves. The signal transmitting layer includes a second electrode layer and a plurality of piezoelectric units formed on the second electrode layer. Each piezoelectric unit includes a second piezoelectric material layer formed on the second electrode layer and a conductive layer formed on the second piezoelectric material layer.
