The red siliceous rocks of the Late Devonian Hongshanliang Formation in the Baogutu tectonic belt, Western Junggar, are extensively developed, comprising approximately 80% of the total stratigraphic thickness. Studying its geochemical characteristics can reveal the genesis of the rock and indicate the tectonic environment, and provide new sedimentary information for the study of the Late Devonian tectonic paleogeographic evolution in the area. The upper siliceous rocks are predominantly red to reddish-brown, with poorly developed bedding, and mainly occur in massive or banded forms. They are often associated with volcanic lava or within volcanic rock interlayers, but no sponge spicules have been observed. The middle siliceous rocks are red, display thin-bedded structures with well-developed stratification, and frequently exhibit sedimentary lamination with abundant sponge spicules. These rocks are interbedded with tuffaceous siltstone and tuffaceous argillaceous siltstone. The lower siliceous rocks, which are red or gray, show transitional lithological and petrographic features between the two aforementioned types. The upper and lower siliceous rocks are relatively low in SiO₂ (71.90%, 87.48%), CaO (1.45%, 1.28%), P₂O₅ (0.09%, 0.06%) and δEu, and high in TiO₂ (0.57%, 0.2%), Al₂O₃ (13.47%, 5.54%), MgO (1.80%, 0.94%), Na₂O (3.93%, 0.64%), K₂O (2.05%, 1.14%), Na₂O/K₂O (1.35, 0.40), Al₂O₃/(Al₂O₃ + ^TFe₂O₃) (0.74, 0.71) and Sc, V, Cr, Cu, Zn, Sr, Y, Zr, La, Ce, Nd, Yb, Lu, ΣREE, Th/Sc, Th/U. The content and corresponding ratio of the major elements in the siliceous rocks in the middle are just the opposite, with high SiO₂ (91%), CaO (2.14%), P₂O₅ (0.48%), low TiO₂ (0.07%), Al₂O₃ (1.05%), MgO (0.32%), Na₂O (0.14%), K₂O (0.14%), Al₂O₃/(Al₂O₃+^TFe₂O₃) (0.37), and significantly depleted in Sc, V, Cr and other elements that are relatively enriched in magmatism. The correlation ratios and graphic analysis show that the volcanism in Hongshanliang Formation had experienced a strong→weak→strong changing process from bottom to top. The upper and lower siliceous rocks are mainly volcanogenic silicon, which are formed in the back-arc basin margin area near the arc volcano, while the middle siliceous rocks are mainly biogenic, which are formed in the back-arc basin environment during the volcanic dormancy period.