In the present work, flexible poly (vinylidene fluoride)/Diamond nanoparticles nanocomposite films with improved electroactive properties at low filler concentration were developed. The combination of nanofiller doping and mechanical stretching was employed to obtain the films with significantly improved electroactive phase at low nanodiamond (ND) concentration, making themthe interesting materials for several applications in the electronic devices. The nanocomposite films with different nanofiller concentration were prepared and then stretched under different stretch ratios. The polar phase content of all films was calculated and compared. It was found that the polar phase fraction of the films was significantly enhanced by increasing the nanofiller concentration and the stretch ratio. Moreover, a finite element model was constructed to determine the true value of the strain during the tensile process and to calibrate the stretch ratio. Development of such nanocomposite films with improved piezoelec- tric properties at low nanofiller concentration can extend their applications for practical usage.