The Triassic in the Kuqa depression is well exposed, mainly composed of terrestrial clastic rocks. Our research focuses on chemical characteristics of detrital heavy mineral in the Triassic sandstones using the electron microprobe. Chemical compositions of the detrital garnets suggest that they mainly comprise almandine, pyrope, spessartine and grossular garnets. They are derived from the low-grade to high-grade metasedimentary rocks and granitoid. The detrital tourmalines are sourced from metasedimentary rocks and granitoid and the parent rocks of the detrital chrome spinels are arc basalt, ocean island basalt and subduction related peridotite. The detrital component of the upper Triassic derived from high-grade metasediments and granitoid is much more than that of the lower Triassic. Comparing with the garnets from eclogite and gneiss in the western Tianshan, the detrital garnets composition has remarkable difference on grossular content with those from eclogite and are similar to those in gneiss, which suggest that the eclogite has not been exhumed at surface yet while the gneiss is well exposed at Triassic time. The detrital chrome spinels in the upper Triassic are mainly derived from arc magmatic rock and ophilite in the central Tianshan and the south Tianshan, some of which are sourced from ocean island basalts, which provide sedimentary evidence for the archipelagic orogenisis of the south Tianshan.