The present invention relates to a torsional vibration resonance frequency measuring method and a novel amplitude transformer for assessing the stability of dental implants. In one example, a torsional vibration resonance frequency measuring method includes installing an amplitude transformer on a dental implant, energizing a torsional vibration mode, gathering resonance signals, and analyzing a resonance frequency. In another example, an amplitude transformer for measuring torsional vibration resonance frequency in a dental implant, includes an anti-rotary horizontal double-winged component and a central bolt. The central bolt is configured to closely connect with the inner threads of the dental implant, such that the amplitude transformer can integrate with the dental implant sufficient to vibrate as an integral structure under energizing.