The structural design and material selection of the piezoelectric layer, backing layer, matching layer, encapsulation layer, and interconnecting electrodes of flexible wearable piezoelectric ultrasound transducers are introduced, the advantages of the simulation design of the transducers using finite element analysis (FEA) technology are discussed, and key technologies in the transducers fabrication, such as electrode patterning, are described. The applications of this type of sensors in the fields of deep tissue imaging, haemodynamic monitoring, promoting the recovery of bone damage, and assisting transdermal drug delivery are analysed. The development direction of the sensors is outlooked, and it is pointed out that in the future, the measurement accuracy, safety and integration degree of flexible wearable piezoelectric ultrasound sensors can be further improved through the application of high?performance signal processing technology, improvement of ultrasound detection and imaging algorithm, and optimisation of the sensor structural design scheme, etc., so as to promote the marketable and industrial development of this kind of sensors.