The eclogites in Southern Sulu ultrahigh pressure metamorphic (UHPM) terrene show very different retrograded microtextures from the corresponding rocks in Northern Sulu, implying different thermal processes. Scanning electron and optical microscope observations indicate that the primary peak assemblage is anhydrous, composed of Grt + OmpⅠ + Ky + Rt (+ Coe). These peak minerals were replaced by the second and third stage minerals, resulting in pseudomorphic symplectite or coronas through the process of OmpⅠ→OmpⅡ + Ab + Fe-oxide symplectite (type Ⅰ), Rt→Rt+Ilm, Ky→Pg; OmpⅡ (+Ab+Fe-oxide)→Hb (+Pl+Fe-oxide) (type Ⅱ), and Grt→Prg+Fe-oxide. In contrast, epidote and quartz were formed at a very late stage as a result of fluid activity along micro-fractures. Mineral chemistry and mass-balance estimation demonstrate that the pseudomorphic textures were developed by metasomatism involving dissolution and precipitation that were intensified by fluids along the grain boundary. The form ation of symplectite by replacing primary omphacite would evidently produce extra Fe, Mg and Na but consume Ca and Si. The extra Mg and Fe (diffused to garnet grains) triggered an interexchange of (Mg, Fe)-Ca of the garnet, resulting in compositional zonation with Ca decreasing towards the edge of garnet grains where the expelled Ca was consumed during symplectite formation. The replacement of kyanite by paragonite consumed the extra Na. At the later stage when more aqueous fluid intruded into the eclogite, fluid infiltration partially converted Symplectite Ⅰ to Symplectite Ⅱ, and a film of pargasite resorbed a garnet from its boundary. Mass balance estimation suggests that the transformation and resorption might have been coupled qualitatively. p-T conditions based on mineral reactions and THERMOCALC software suggest that the retrogression of the eclogite occurred under HP conditions. The difference in p-T path between the Southern and Northern Sulu eclogites suggests the existence of different exhumation historis within the Sulu terrene.