The Drilling Well of Tacan 1 (TC-1 for short) was an exploration well in the central part of the Tarim Basin, NW China. It was 7200 m in depth and the deepest well on shore in China, so far. Its systematic core extracted was an important window for the studies on Tarim geology. The Silurian-Devonian clastic rocks were revealed from the depth of 3742 m to 4001 m, including 125 m of Lower Silurian and 134 m of Upper Devonian. Total 23 specimens (15 of Lower Silurian and 8 of Upper Devonian) were collected for chemical analysis. The geochemical data showed that the sedimento tectonic setting was an inner-cratonic environment. Namely, the Silurian and Devonian clastic rocks in the TC 1 area were deposited on a stable continental crust. The provenance might be the uplifted Pre Sinian basement rocks, which were represented by the granitoids revealed at the bottom of the TC-1.