An electronic device includes an energy collection circuit, a rectifier circuit, and a control unit. The energy collection circuit receives an energy signal transmitted via transmission frequency from a wireless charger base. The rectifier circuit generates a drive voltage according to the energy signal. The control unit compares the drive voltage with a reference voltage, and compares the transmission frequency with a reference frequency. When the drive voltage is less than or equals to the reference voltage, or when the transmission frequency is lower than or equals to the reference frequency, the control unit outputs position deviation information. The electronic device detects the efficiency of the wireless charging, and reminds the user whether the position of the electronic device needs to be adjusted, which ensures an efficient charging.