The Early Cretaceous-Early Eocene granitoids in the Tengchong Block record the evolutionary history of the Mesozoic-Cenozoic tectono-magmatic evolution of Eastern Tethys.(a)The Early Cretaceous grani-toids with relatively low(87Sr/86Sr)i ratios of 0.7090-0.7169 and εNd(t)values of-9.8 to-7.8 display metaluminous,calc-alkaline dominated by Ⅰ-type granite affinity and hybrid mantle-crust geochemical signatures.They may have been derived from melting of the subducted Meso-Tethyan Bangong-Nujiang oceanic crust with terrigenous sediments in an arc-continent collisional setting.(b)The Late Cretaceous-Paleocene granitoids with relatively high(87Sr/86Sr)i ratios of 0.7109-0.7627,and εNd(t)val-ues of-12.1 to-7.9 exhibit metaluminous to peraluminous,calc-alkaline dominated by S-type granite affinity and hybrid Lower-Upper crust geochemical signatures,which may be originated from partial melting of the Meso-Proterozoic continental crust in the collision setting between the Tengchong Block and Baoshan Block.(c)The Early Eocene granitoids have metaluminous,calc-alkaline Ⅰ-type and S-type granites dual affinity,with relatively high(87Sr/86Sr)i ratios of 0.711-0.736,εNd(t)values of-9.4 to-4.7,showing crust-mantle mixing geochemical signatures.They may have been originated from par-tial melting of the late Meso-Proterozoic upper crustal components mixed with some upper mantle mate-rial during the ascent process of mantle magma caused by the subduction of the Neo-Tethyan Putao-Myitkyian oceanic crust,and collision between the Western Burma Block and the Tengchong Block.It is these multi-stage subductions and collisions that caused the spatial and temporal distribution of the granitic rocks in the Tengchong Block.