A compact auto focus lens module with a piezoelectric actuator revealed includes a piezoelectric actuator, an elastic element, at least two guiding fixtures, and a lens barrel with an optical lens set therein. By elastic force of the elastic element, a friction is generated between the lens barrel and the piezoelectric actuator. While being applied with a voltage, the lens barrel driven by the movement of the piezoelectric actuator moves along the optical axis under the guidance of the guiding fixtures. Due to fewer elements, compact volume, and light weight, the design is applied to miniature auto focus lens modules so as to achieve effects of fast movement, stable focusing and reduced tilting.