The LDWS(Lane Departure Warning System) is an assistant system that gives a warning to a driver for safe driving when a vehicle breaks a lane away. This system consists of CIS(CMOS Image Sensor), DSP(Digital Signal Processor), and MCU(Micro Control Unit, CPU). The CIS gets various image signals from the front camera and transforms into digital signals. And then it sends those signals into DSP component. The DSP calculates image signals from CIS and determines whether a vehicle breakes a lane away or not. Also, it receives various vehicle's signal,such as vehicle speed signal, wiper signal and turn signal, and when it judges that the vehicle breakes a lane away, the DSP controls a buzzer and an indicator for safe driving. The MCU has a function to improve its processing ability in order to deal with its images much more effectively.