Abstract: The silicalite and siliceous mudstone of Devonian Daminshan Formation are developed in northern Daxinganling, where the siliceous mudstone is rich in marine fossils. The Al/(Al+Fe+Mn)values of the siliceous rocks range from 0.60 to 0.71, with an average of 0.65. In the Al-Fe-Mn ternary diagram, all samples fall into non-hydrothermal siliceous rock area. The MnO/TiO₂ ratio is 0.07-0.34, and 0.18 in average. The m value is 13.87 to 47.15, averagely 23.90. The CaO/(Fe+CaO) value is between 0.65 and 0.98, with an average of 0.78. The ΣREE is low (averagely 62.77×10^-6) and the average LREE/HREE is 6.67. The siliceous rocks are relatively enriched in LREEs, with slightly positive Ce anomalies (δCe 1.08-1.30, averagely 1.16). Combined with the sedimentary environment discrimination diagram for siliceous rocks, it is indicated that the siliceous rocks of Daminshan Formation are formed in the continental slope close to continent or the high-salinity seawater of marginal sea.