With the continuous popularization and development of PEPS technology in the automotive market，passive entry and passive start are already available on more and more models. In addition to this, the welcome feature that has emerged is also being used more and more. The traditional intelligent key is not highly integrated and can not meet the market demand for new functions. In order to meet the needs of market development, adopt the real single-chip intelligent vehicle access control solution of NXP semiconductor, namely NCF29A1. It combines a keyless system (PKE), a remote-controlled RF transmitter, and an anti-theft lockout system, enabling a true single-chip solution that greatly simplifies the hardware design circuit. This design uses NCF29A1 as the main control chip to realize the software and hardware design of the smart key. In order to meet the latest design requirements of the market, functional aspects include RKE, PKE, PS, IMMO anti-theft, welcome function, etc. And in terms of cost and performance, due to the selection of the latest NCF29A1 single-chip solution, the static power consumption of the key is reduced and the service life of the key is extended. It has the characteristics of low cost, excellent performance and easy expansion.