Based on the study of Silurian outcrop at Kalpin area at the northwest of Tarim Basin, Xinjiang, 15 ichnogenus and 28 ichnospecies, namely, Asterichnus lawrencensis, Cochlichnus anguineus, Cruziana ichnosp., Cruziana qinlingensis, Cruziana rouaulti, Diplichnites bipartibilis,Gordia molassica, Helminthopsis abeli, Helminthopsis isp., Lockeia siliquaria, Monocraterion cf. teataculatum, Palaeophycus tubularis, Planolites isp.,Planolites montanus, Planolites punctatus, Rusophycus ramellensis,?Scolicia ichnosp., Sagittichnus lincki,Spirophycus bicornis and Taenidium cameronensis,were discovered in Kalpintage Formation. According to the composition, occurrence and distribution characteristics of these trace fossils and their country rock features, two types of ichnoassemblages under different sedimentary environments have been recognized as follows:(1) Helminthopsis-Gordia ichnoassemblage, including such common trace fossils as Asterichnus, Diplichnites,Gorida,Helminthopsis, Planolites, Rusophycus,?Scolicia and Spirophycus, generated in deep water shelf sedimentary environment far away the shore with lower energy; and (2)Cruziana-Rusophycus ichnoassemblage, containing such trace fossils as Cochlichnus, Cruziana, Palaeophycus, Lockeia, Rusophycus,Monocraterion,Sagittichnus and Taenidium, formed in shallow water shelf sedimentary environment.