LA-ICP-MS in situ trace element analysis was performed for minerals in eclogite from Somdo. According to the results, garnet mainly contains MREE, HREE and Y, with high concentrations of Sc, V, Cr and Co; omphacite contains high concentrations of MREE, Sr, Sc, V, Cr, Co, Ni and Ti, with certain amounts of Zr and Hf; garnet, omphacite, amphibole and epidote all exhibit LREE depletion, indicating the nonexistence of metasomatism by exotic LREE-rich fluid during the retrogressive metamorphism of the eclogite, and this accounts for somewhat different trace element characteristics between eclogite here and Su-Lu UHP eclogites that are characterized by LREE enrichment. Zoning of some trace elements(e.g., Ti and Zr)demonstrates the pressure decreasing and temperature increasing closely after peak metamorphism during the turning back to the shallow position. Trace element partitioning between rock-forming minerals is controlled by the partitioning of major elements between minerals, e.g., MgO partitioning between garnet and omphacite controls the partitioning of Ni, Co, Ti, whereas CaO partitioning controls the partitioning of Sr, Y and REE. The formation and decomposition of minerals and the change of physical-chemical conditions might result in new partitioning of trace elements between minerals during retrogressive metamorphism. Amphibole formed by omphacite retrogression would not wholly inherit the trace element distribution pattern of omphacite without any diversification, as indicated by differences in their trace element distribution patterns; nevertheless, the somewhat similar specific characteristics of trace element distribution patterns between omphacite and amphibole demonstrate their certain genetic linkage. Rutile is the main bearer of HFS elements such as Ti, Nb, Ta, Zr and Hf, which strongly effects the depletion of HFS elements in coexisting epidote.