A power supply and data signal transmission method used in an induction type power supply system consisting of a power supply module and a power-receiving module for transmission of electrical energy and data signal is disclosed. The microprocessor of the power supply module scans the resonant point of the power supply coil to send a segment of energy for recognition of a feedback signal from the power-receiving module and then starts providing power supply after receipt of the feedback signal, and then runs further signal modulation, transmission, data decoding and other follow-up steps, achieving transmission of electrical energy and data signal wirelessly.