The invention relates to a magnetically coupled non-resonant rotary piezoelectric generator, and belongs to the technical field of power generating. A rotating shaft is installed on a bottom shell, arotating disc is installed at the end part of the magnetically coupled non-resonant rotary piezoelectric generator, and an exciting magnet is welded on the end surface of the rotating disc; the rightside of the shell body is installed on the bottom shell, and an end cover is installed on the left side of the shell body; a threaded hole is formed in the top end of the shell body, and a raised table is arranged on the inner side of the shell body; an adjusting bolt extends out of the inner part of the shell body through the threaded hole, and a lockage nut is arranged outside the shell body ina spiraling mode; a circular raised table arranged on the bottom of the adjusting bolt extends into an opening of a loading block; the two ends of ferromagnetic substrate are correspondingly installedon the loading block and the raised table, lateral displacement of the ferromagnetic substrate is limited through a guiding block arranged on the middle of the ferromagnetic substrate, and thus the ferromagnetic substrate is divided into an upper piezoelectric oscillator and a lower piezoelectric oscillator; the guiding block is installed on the end cover; the upper piezoelectric oscillator and the lower piezoelectric oscillator are formed by bonding of the ferromagnetic substrate and a piezoelectric crystal plate, and the piezoelectric crystal plate is arranged on the left side of the ferromagnetic substrate; when the adjusting bolt is adjusted to an upper limit position, the upper piezoelectric oscillator and the lower piezoelectric oscillator are in elastic deformation, and when the adjusting bolt is adjusted to a lower limit position, the upper piezoelectric oscillator and the lower piezoelectric oscillator are in the largest allowable compressive stress range.