Based on summing up of petrography and petrochemisty for mantle peridotite all over the world, we firstly propose a diagram for discriminating the protolith of metaperidotite of HP and UHP metamorphic terrane. This diagram is constituted by total MgO+(%) versus (m+f)/si ratio. Two additional diagrams, consisting of Al2O3 versus MgO+(%) respectively, are used to divide the boundary between harzburgite and lherzolite. By discriminating the protolith of metaperidotite from the PP3 hole and PP1hole, we found a large sum of differences existing in metamorphic mineral assemblage, protolith genesis, geochemistry and metamorphic conditions among them, which represents two extremely different geochemical types and distince tectonic environment, respectively. The metaperidotite from the PP3 hole, being garnet bearing dunite, has assemblage of Ol+Gr+Cpx+Opx+Sp. Its protolith is the product of residual mantle harzburgite which suffered UHP metamorphism. The garnet bearing dunite is characterized by highly uniform composition, enrichment in MgO (Mg'=92), and extreme depletion in incompatible REE (total REE abundances to lower than 1 ppm). The residual Crsp, still preserved in the metaperidotite, has the compositional features of typical ophiolitic duniteharzburgite, with coexistence of garnet and spinel. In view of the experiments by Klemme et. Al. (2004), spinel coexisting with garnet is stable up to 7GPa at 1400℃，which means the metaperidotite from PP3 hole is formed no more than 200km. Comprehensive studies show that the metaperidotite (its protolith to be harzburgite possesses the attribution of oceanic lithosphere mantle, but is not the transition phase of the mantle at 200km depth.The metaperidotite from PP1 hole, being garnet peridotite complex, has assemblage of Ol+Gr+Cpx+Opx anhydrous phase and Phl+Ti+Chu hydrous phase. Based on the discrimination of their protolith, they are found to derive from two different genetic ultramafic series: one is harzburgitelherzolite from continental mantle wedge; the other is dunitewehrlitepyroxenite deriving from magmatism. The garnet peridotite is characterized by highly inhomogeneous composition, extreme enrichment in REE (total REE abundances > 20ppm) and LIL. This does not reflecting the geochemical features of their protolith, which is contaminated by continental crust during subduction, or crustmantle interaction. According to the fact that the rock from PP1 hole lacks of spinel phase, and symbolizes with garnet phase, we can conclude that the rock is formed at pressures of more than 7GPa, over 200km in depth.From the above results, it shows that in the Sulu UHP metamorphic belts, there exist metamorphic teranes not only from continental mantle wedge, but also from ophiolitic mantle as the front of continental subduction slab. This research provides new information for revealing the formation and evolution of the UHP metamorphic belt.