In these few decades, the vehicle number is rapidly increasing because people’s incomes are increasing. In addition to the vehicle number, more factors of road situation, driving environment, and human attention result in a large amount of traffic accidents and casualties. If there is a mechanism to help the driver to detect the road situation and driving environment, and then to provide some useful information to the driver in these situations, the danger is therefore avoided. In this thesis, we set up one camera on the vehicle to capture images for detecting traffic sign with red color border and recognize the speed in speed limit traffic sign.