With the continuous development of science and technology, the car entry system is also constantly upgraded. As a new way to enter the car, NFC card key has the advantages of convenience, safety and so on, and has gradually attracted attention. This paper first introduces the basic principle of NFC technology, and then introduces the design scheme of NFC card key intelligent entry system, including its system scheme and working principle. Finally, the challenges NFC card key in the field of vehicle application are explained.