Abstract: A Middle Triassic Ladinian radiolarian fauna consisting of Sepsagon robustum Lahm, Triassocampe cf. coronata, T. cf. levigata, Pararuesticyrtium cf. trattoense and Hindeosphaera spinulosa is discovered in an association of low-grade metamorphic foliated quartzose sandstone, silty mudstone and (pebbly) feldspathic lithic graywacke with cherts, andesite, pebbly basic lithic tuff, andesitic lithic tuff and basalt. The discovery of the radiolarian fossils has great significance for the stratigraphic division and correlation of the Triassic and study of tectonic evolution in the northern Qiangtang area.