New findings of the early Silurian Xiyuichthys (Xiushuiaspidae, Galeaspida), Xiyuichthys lixiensis sp. nov. and X. zhangi are described from the Qingshui Formation in Jiangxi Province and the Tataertag Formation in Tarim Basin respectively. X. lixiensis sp. nov. is characterized by the partially serrated lateral margin of the headshield and the ornamentation composed of extremely coarse granular tubercles (one tubercle per square millimetre). The complete early Silurian biostratigraphic sequence in northwestern Jiangxi warrants the erection of a standard section for the correlation of Silurian shallow marine red beds in South China and Tarim blocks. Thus, the finding of X. lixiensis from the Qingshui Formation (Silurian Lower Red Beds) in Jiujiang of Jiangxi bears important biostratigraphic significance. It can directly compare to X. zhangi from the Tataertag Formation in Tarim Basin on the specific level, which corroborates the correlations between the Tataertag Formation in Tarim Block and the Silurian Lower Red Beds in South China. Fossil records suggest that Xiushuiaspidae have a relatively broader stratigraphic range, but exhibit distinct composition at different stratigraphic horizons, with Xiyuichthys and Changxingaspis arising in the Silurian Lower Red Beds (Qingshui, Tangchiawu, and Tataertag formations) and Xiushuiaspis occurring in the Silurian Upper Red Beds (Xikeng Formation).