The invention provides a strip steel width information detecting method based on an embedded system and a gigabit ethernet. An embedded image processing part and a data communication part are arranged. A digital signal processor (DSP) is designed as an embedded strip steel width detection control system of a core device. With the DSP, a high-speed linear array CCD camera is controlled to collect image information of a steel plate; strip steel image edge searching algorithm analysis and processing are carried out by the DSP to obtain strip steel width information; and then with the gigabit ethernet, the processed strip steel width information is transmitted to an upper computer to provide the support for production. The method has advantages of high integration, small board dimension, goodanti-interference capability, high system data transmission capacity, and fast speed and is capable of realizing on-line width detection of the steel plate with the detection precision of 0.5mm; lotsof system resources are saved; and the structure is simple and the maintenance is carried out conveniently.