A wearable ultrasonic sensing device includes a first protective layer, an ultrasonic receiving unit, a circuit board, an ultrasonic sending unit and a second protective layer. The ultrasonic sending unit includes a first electrode layer, a first piezoelectric layer and a second electrode layer, which are stacked in that order. The first electrode layer includes a plurality of electrode units which are spaced apart from each other. The first piezoelectric layer includes a plurality of piezoelectric units, and there are several piezoelectric units located between each electrode unit and the second electrode layer. Each electrode unit, the second electrode layer and the piezoelectric units between the electrode unit and the second electrode layer cooperatively form a piezoelectric sensing unit.一種穿戴式超音波感測裝置，其包括依次層疊設置的一第一保護層、一超音波接收單元、一電路基板、一超音波發射單元及一第二保護層，所述超音波發射單元包括依次層疊設置的一第一電極層、一第一壓電材料層及一第二電極層，所述第一電極層包括多個間隔排布的電極單元，所述第一壓電材料層包括多個壓電單元，所述每一電極單元與所述第二電極層之間夾設有多個壓電單元，每一電極單元、所述第二電極層及夾設於所述電極單元與所述第二電極層之間的多個壓電單元構成一個壓電感測單元。
