Large solid rocket motor （SRM） is well suited to space exploration mission because of simple architecture，large thrust， and high reliablity. Large throat is a key technology for the nozzle. This paper presents an overview of large SRM nozzle and throat international preparation，materials property， characterization of large SRM nozzle and throat in France， Japan，USA， India.Chinese large SRM throat technology was summarized， and directions for large throat design and material preparation are given.