Abstract: Ultrahigh- pressure (UHP) metamorphism refer to those metamorphic pressure is higher than 2.5Gpa because of ultradeep conditions. Coesite , metamorphic diamond and other UHP mineral or mineral assemblages typify their collisional origin. In China, Dabie—Sulu collisional orogenic belt developes the most well-exposed and largest in scale UHP metamorphic belt in the world. The development of the UHP metamorphic belt indicates that in the mid –Triassic time the Yangtze craton was deeply subducted beneath the Sino-Korea craton implying that voluminous crustal materials had deeply subducted to a mantle-depth up to 150Km. The careful study of those petrological records remained in the UHP metamorphic rocks reveals their formation, uplift and exhumation processes. From these information the metamorphic PT path and an” active compression and then active extension” 4-stage tectonic evolution model can be reconstructed. Therefore, the study of UHP metamorphism had provided new prospect for the theory beyond plate tectonics onward the continents. And UHP metamorphic study had become a new hot-spot in the field of Earth science.

Key words: Ultrahigh-pressure metamorphism, collisional orogenic belt,Dabie-Sulu,deep subduction,uplift and exhumation,continental dynamics