Abstract:  At the present time, automatic highway toll card system often lacks of measures to control the driver to steal many charging cards more than usual one. So, we propose a security card system that one car only can get a single card. This design uses an additional traffic direction detection device with the original automatic card machine, forms an antitheft security card system to protect the driver maliciously steal the highway charging cards, and reduces the economic losses of the highway company. The system has a stable and reliable design, and has dozens of them are used in Fujian Funing highway toll station, and has obtained a good effect.