The invention provides a multilayer piezoelectric thin film 
cantilever beam sensor and a preparation method therefor. A sacrificial layer releasing process is adopted to release the sacrificial layer from the front surface to form a piezoelectric micro-
cantilever beam structure; the commonly-adopted 
CMOS process is fully utilized, so that the process is simple and controllable; the compatibility between the 
piezoelectric cantilever beam sensor manufacturing process and an 
silicon integrated circuit process is improved; the problem of 
pollution existing in a process that the bulk-
silicon substrate is etched by a wet 
etching method and the 
cantilever beam is released from the back surface is avoided; in addition, the multilayer piezoelectric thin film and a flexible supporting layer are adopted, so that the sensitivity of the sensor or the deformation amplitude of an 
actuator is improved, and the response of the cantilever beam to external excitation and the 
signal output are improved; in addition, due to the flexible supporting layer, the structure and the 
processing technology of the sensor are simplified; and the piezoelectric micro-sensor adopting the structure can be applied to objects of any sizes and any surface shapes, so that the application range of the micro-sensor is expanded.