Abstract: The gypsum-salt rocks are developed in the Middle Cambrian in Tarim basin, and their distribution and sealing capacity are of great significance for the petroleum exploration in deep formations. By using mud logging, wireline logging, seismic, and well test data, the distribution and sealing capacity of gypsum-salt rocks are analyzed. Furthermore, the quality of gypsum-salt cap rock is evaluated from the perspective of rock type (i.e., salt rock, gypsum rock, and gypsum-bearing rock), burial depth, and tectonic deformation intensity. The study results indicate that: (1) The sedimentary sequence of gypsum-salt rocks in the Middle Cambrian in Tarim Basin is composed of salt rock, gypsum rock, gypsum-bearing rock, dolomite, limestone and mudstone, which is mainly distributed in the central Tarim Basin, with a small distribution range of salt rocks only in the central part, a slightly larger distribution range of gypsum rocks, and a largest distribution range of gypsum-bearing rocks, showing the characteristics of bull-eyed deposition pattern; (2) The superior gypsum-salt cap rocks are developed in the central-western Northern Depression, most areas in the central-western Central Uplift, and the north slope in the western part of Southwestern Depression; The medium-quality gypsum-salt cap rocks are developed in local areas in the central part of Central Uplift and the northern part of northwest structural belt in the eastern Southwestern Depression; The poor gypsum-salt cap rocks are developed in the central Tabei Uplift and the southern part of northwest structural belt in the eastern Southwestern Depression.