With the rapid development of communication technology,optical communication system also has higher requirements for transmission distance,channel capacity and transmission rate.In order to solve these problems,it is necessary to study FEC code scheme with better performance.Concatenated code is a code types which has good performance in correcting burst and random errors,and can maintain low redundancy, so it has become the main research object.Based on the concatenated code of ITU G.975.1 standard,we proposed two new RS-BCH codes,made comparison and analysis in theory,and carried out corresponding modeling and simulation.One was the concatenated code of RS (255,239) code and BCH (31,16) code,and the other was the concatenated code of RS (255,239) code and BCH (511,448) code.The error correction performance of the two concatenated codes has been greatly improved compared with that of the single RS (255,239) code and the original code,and the latter has moderate redundancy and is easy to implement,which is more suitable for high-speed optical communication systems.