Siliceous rocks are a rock type so widely distributed in the Jinsha River orogenic belt that the determination of its sedimentary environments is of important significance to the study of deep-sea deposition, continental-margin geology and tectonic frame work. Study on the lithology, pa-leoecology of radiolarian assemblages, REE geochemistry and sedimentary association of siliceous rocks in this orogenic belt has proved that the Jinsha River suture zone could not have formed the main suture zone in the Paleo-Tethys domain.