To meet the demands of rotating machine for self-powered monitoring system, a novel piezodisc generator excited by the coupling effect between rotating magnets and those fixed on the piezodisc was presented. The influence of system factors on the maximal voltage and total energy generated from the piezodisc at one excitation was investigated mainly. The research results show that both the output voltage and effective speed-band can be enhanced with increasing magnet size or decreasing the distance between the magnets. In this way, output voltage beyond 12 V was obtained at rotating speed range of 100-2850 r/min. Besides, the thickness of the piezodisc exerts also great influence on the generated voltage and electric energy. Both the maximal voltage and total electric energy can be enhanced with using a thin piezodisc at low speed or a thick piezodisc at high speed. The optimal speeds for the piezodiscs of 0.2/0.4/0.6 mm in thickness to obtain maximal energy are 707.5 r/min，1301.8 r/min，2490.4 r/min respectively. At the optimal speed and one excitation, the obtained energy/power from the 0.2mm-thickness piezodisc are 3.1/1.7 and 6.4/2.0 times those from the 0.4mm and 0.6mm thickness piezodiscs. Taking 5V output voltage for example, the usable energy generated from the 0.4mm-thickness piezodisc is 5 times that from the 0.6mm thickness piezodisc at 912 r/min. While, the usable energy from the 0.6 mm-thickness piezodisc is 1.7 times that from the 0.4mm thickness piezodisc at 1710 r/min.