Magnetic energy harvesting (MEH) circuit for system sustainability and power monitoring system with a novel dual-wire current transformer (DWCT) are proposed in this paper. MEH circuit simultaneously senses and harvests the magnetic energy. DWCT has the benefits of non-invasion measurement (NIM) and is easy to use. The designed direct AC-DC rectifier with maximum power extracting (MPE) control fits the characteristic of magnetic energy source. Thus, 120% harvesting power improvement can be achieved under the same sensing current.