Lying in a distinctive tectonic locality within the collisional belt between the India and Eurasian plates, the Myanmar jadeitites deposit is one of the largest and most important jadeite deposits in the world. It has been shown that the Myanmar jadeitites formed during the subduction of the Neo-Tethys oceanic crust when peridotites experienced high-pressure metamorphism and metasomatism. In this paper, a fluid inclusion study of the Myanmar jadeitite samples with variable deformation degrees was carried out and, as a result, four types of fluid inclusions were identified: ① low-salinity aqueous inclusions with or without minor CH₄ (type Ⅰ), the primary type Ⅰ inclusions occur either as isolated ones or in clusters in the core or along the growth zones of jadeite crystals with primary growth textures; ② three-phase H₂O±CH₄ inclusions with halite daughter crystals (type Ⅱ); ③ pure CH4 inclusions which can be subdivided into high-density ones (type Ⅲa) and low-density ones (Ⅲb); ④ gaseous or empty inclusions (type Ⅳ). This investigation revealed that several fluid events occurred during the formation and evolution of Myanmar jadeitites and related rocks. A fluid phase that originated probably from sea water should have been present during the formation of jadeitite in the high-pressure metamorphic-metasomatic process of peridotite; the high-salinity aqueous inclusions and high-density CH₄ inclusions were recognized for the first time in the Myanmar jadeitites, the high-salinity aqueous fluid was probably related to the recrystallization process of the jadeidite, and the preserved high-density CH₄ in the jadeitite was probably generated as a by-product of serpentinization of ultramafic rocks in the mantle wedge above the subducting slab, coupled with the complete consumption of water during hydration of serpentine. The calculated fluid inclusion isochores suggest that various degrees of reequlibration of these fluid inclusion occurred during the evoluition of the jadeitites.