Abstract: The smart car uses FREESCALE's MC9S12DG128 as the core controller chip and OV7620 digital camera for path identification. The core control chip collects data to analyze and extract the black center line, and then filters the irregular black interference signals. Judging the shape of the line accurately is able to control the steering wheel and motor and let the car move stably and fast. The strategy for vehicle speed control system is introduced, and the choice of the control strategies is analyzed and improved by comparing testing look-up table PID control strategy with fuzzy PID control strategy. The final choice is the fuzzy PID control strategy through specific test and observation. As a result, the identification of straight track, curved track is realized, and the effect is improved, especially in corners where the body can keep stable and the speed is greatly enhanced.