The southwestern Tianshan high- and ultrahigh-pressure metamorphic belt is a rare example of metamorphosed accretionary mélange exhumed from great depths, as a result of the closure of the paleo-Tianshan Ocean. The internal structure of the subduction complex is still controversial. Taking a~4 km-long N-S cross section in the Muzaerte area as an example, this paper summarizes the field occurrences, mineralogy and metamorphic evolution of the southwestern Tianshan high- and ultrahigh-pressure metamorphic belt. These studies suggest that there expose two types (i.e., UHP and HP) of lawsonite eclogites, but most of them were strongly retrogressed and deformed at blueschist- and greenschist-facies conditions. These metabasic rocks constitute two eclogite belts, including northern and southern, that are separated by a fault. The Muzhaerte UHP lawsonite eclogites and their host rocks experiencedsimilar peak metamorphism, constituting the western termination of the UHP metamorphic belt of southwestern Tianshan. Compared with the eastern Akeyazi UHP eclogites, they are different in terms of deformation features, rock assemblages and metamorphic experiences, probably indicating that deeply subducted slab occurred different metamorphic and transform evolution along-strike variations of tectonometamorphic processes during exhumation. These results are fundamental to unravel the metamorphic evolution of subducted accretionary mélange and related geodynamics during slab subduction and uplift.