sulfur isotope analysis was made for various types of gypsum.anhydrite and polyhalite from four drill holes in this reconnaissance area.This pager descrihes δ34S characteristics of veinlike anhydrite，anhydrite and hydrated anhydrite, suggesting that gypsum was mainly formed by the hydration of anhydrite under the action of underground water. The microscopic observations of poly halite, its texture and structure and its sulfur isotopic composition all paint to the existence of "primary" polyhalite and the extensive develop ment of secondary polyhalite(replace ment type). Sulfur isotope studies of anhydrite fro m various sections of Triassic in this area indicate that δ34S values of T1j4-T2l1 are comaratively stable (between 29-31%)，implying a shallow-water and salinized sedimentary environment. After T2l2,δ34S values tended to decrease progressively. Such evolutionary regularity is consistent with things in other areas of Sichuan basing suggesting a transgression-regression salt-forming environment It is thus concluded that δ34S values and charcteristics of anhydrite may serve as indicators to divide strata,especially strataof evaporates. This result has added to and enriched the knowledge sulfur isotope composition and evolution of marine Triassic sulfates in the world.