Abstract: On the basis of actual demand for long-distance transmission of high definition LED screen, In order to solve the problem that the longest transmission of 1000BASE-T is 100 meters, using optical fiber which has longer transmission distance instead of 1000BASE-T. In the light of cost, the original structure of the sending and receiving system was not changed. A design of fiber converter of gigabit Ethernet was presented, which has implemented the conversion of UTP and fiber with the design of conversion of data format and control module based on FPGA. This converter is used for real-time digital video transmission system of high definition LED screen with reasonable effects, implementing real-time digital video transmission up to 10km，meeting the needs of users in a certain future, achieving the expected target of this design.