Abstract: The siliceous rocks are widely developed in strata of different ages in the northeastern JianXi Province．Their Si02 contents are in the range of72．2％ ～97．19％ ，and their Si／Al ratios are 10．84～9321．The Si02 contents are well negatively correlated with A]2O3 contents．This implies that these rocks have a source with higher proportion of terrestrial muddy sediments．Some geochemical characteristics of these siliceous rocks ale shown below： AL2O3／( AL2O3+Fe203)=0．60～0．99，Ce／Ce =0．99～1．22，(La／Ce)N=0．91～1．83；V／Y<5．78，Ti／V>17．These characteristics indicate that they were formed in a tectonic environment of continental margin．There is no relation with the deep oceanic basins and／or mid-ocean ridges．Since the Paleozoic the tectonic environment of deep oceanic basins was not developed in this region．