The conceptions of (Late Triassic) “Carnian Carbonate Productivity Crisis” or “Carnian Pluvial Event” were proposed by European geologists, based on the research on the Carnian of Alpine Region. The similar lithological change from carbonate rocks to black shale (or green shale and radiolarites), then terrigenous clasolite was widely seen in Eastern Tethys Region (SW China), which had not been paid attention to. Similar to the Carnian in Western paleotethys Area and Himalayan Spiti Basin, Carnian carbonate deposition(e.g. sponge reef limestone, platform carbonate rocks) in SW China was covered by grayish black, dark gray shale (or slate), and clasolite, which showed the termination of the carbonate production and the sudden death of reef. It was deduced in this paper that the Carnian Carbonate Productivity Crisis was triggered by the orogeny occurred in Tethys region and by the megamonsoon effected by the global (especially Tethys) tectonic movements. More watery climate effected by the megamonsoon would be in charge of more remarkable continental weathering, which caused more clay and siliciclastic material inputting into Tethys Ocean and reacted on this Carnian Carbonate Productivity Crisis.