Wireless power supply is a convenient and secure power supply application of new technology. It does not require any physical connection. Electrical energy can be transferred to electrical appliances at close range and without contact. More importantly, wireless power transmission can be conducted through the non-metallic material, which is very convenient. Now the main wireless power supply schemes are electromagnetic wave program；magnetic coupling scheme; non-radiative resonant magnetic coupling scheme in view of simpleness, easiness, and operability. The wireless power supply in this paper is mainly based on the principle of electromagnetic induction, and we designed a simple wireless power supply system. As long as the distance between the emitting and receiving coils is in the 27cm or less, it can be a stable output voltage of 5V DC and the transmission efficiency of approximately is 38.7%.