Abstract: Few geological researches in Kayakedengtage area of East Kunlun Mountains have been carried out, and especially there has no Late Devonian intrusive rock been reported or recorded in the past. According to the LA-ICP-MS zircon U-Pb isotopic dating, this paper identifies the existence of Late Devonian granodiorite, forming in 380.52±0.92 Ma of Late Devonian. This discovery challenges the previous understanding that the mantle-derived magma underplating of East Kunlun Caledonian orogenic cycle occurred in the early Devonian (408 Ma) to middle Devonian (386 Ma), instead, it is confirmed that the mantle-derived magma underplating continues to the late Devonian (380 Ma), which lays a foundation for the refinement of the late Devonian tectonic background of the East Kunlun Qimantage Caledonian orogenic cycle. Late Devonian granodiorite in Kayakedengtage occurred in the mantle-derived magma underplating of later post-orogenic extension collapse of Qimantage Caledonian orogenic belt.