This study presents zircon U-Pb age of the gneissic granites from the Tengchong block, western Yunnan. Field survey and their petrographic features imply that they should be from magmatic origin, and undergone anatexis later. Of the 24 points on 24 zircon grains, 1 points of inherited ziron yielded 206Pb/238U age of 537.5±5.6Ma, and 2 points of magmatic zircons yielded wtd 206Pb/238U age of 456Ma, and 3 points of anatectic zirons yielded wtd 206Pb/238U age of 117Ma, and 18 points of anatectic zirons yielded Robust (Median) 206Pb/238U age of 66.2+7/-4Ma. It suggested that the granites were formed in the early Paleozoic, and anatexis happened in the Cretaceous probably. The anatexis envent maybe related to the magmatism of the Tethys during the Cretaceous.