The Dongqiao ophiolite, located in the northern part of the middle segment of the Bangong- Nujiang suture zone, comprises a suite of lithologies, including harzburgites, dunites, chromitites, gabbros, pyroxenites, basalts, and minor silicitic units. The high- chromium chromitites are mostly densely impregnated, with some occurrences as dense blocks, while the high- aluminum chromitites are smaller in size and exhibit both dense and sparsely impregnated. Both chromitite types are enveloped by dunites and are distributed in lenticular forms within the harzburgites. Chemical analyses of chromium spinel from the Dongqiao chromitite reveal the presence of both high- chromium (Cr# values ranging from 60. 7 to 79. 8, Mg# values from 57. 2 to 68. 1) and high- aluminum varieties (Cr# values from 56. 4 to 59. 6, Mg# values from 67. 2 to 72. 7). In the transition zone between dunite cladding and banded disseminated chromitite, an increase in Cr# values (67. 2~68. 5) and a decrease in Mg# values (57. 4~74. 6) are observed. This suggests that the mantle peridotite and its associated chromitite have undergone varying degrees of melt- rock interaction. The olivine Fo values in harzburgites range from 91. 2 to 92. 3, with corresponding chromium spinel Cr# values of 70. 2 to 75. 1. In dunites, the olivine Fo values range from 92. 7 to 92. 9 and the chromium spinel Cr# values range from 75. 4 to 76. 6. These values are broadly consistent with those observed in the Dingqing, Qielihu, and Yilashan massifs in the Banong- Nujiang suture zone, indicating similar formation conditions for the Dongqiao mantle peridotite. The Dongqiao mantle peridotite exhibits rare earth element characteristics typical of pre- arc mantle peridotite, with trace element compositions closely resemblingthose found in the Izu- Bonin- Mariana. This suggests that the Dongqiao ophiolite may have formed in an ocean floor- spreading environment above a subduction zone. The platinum group element (PGE) patterns of the chromite display a strong affinity to those observed in Luobusa chromitites, characterized by enrichment of IPGE and depletion of PPGE. Equilibrium melt analysis of the Dongqiao mantle peridotite and chromite suggests that the high- chromium chromitite formed in a subduction zone island arc (SSZ) forearc basin environment, while the high- aluminum chromitite may have formed in a mid- ocean ridge (MOR) environment. The juxtaposition of these lithologies within the Bangong- Nujiang suture zone provides compelling evidence for a multi- stage MOR- to- SSZ evolutionary process that affected the Dongqiao mantle peridotite and its associated chromitites.