The Baiyunshan ophiolite mélange is a part of the Hongliuhe-Niujuanzi-Xichangjing ophiolite belt in the Beishan orogenic belt and has a complete sequence composed of serpentinized lherzolite, serpentinite, gabbro (cumulate gabbro, massive gabbro), mafic pillow lavas (metabasalt) and bathyal-abyssal or pelagite-hemipelagite facies sediments (silicalite, slate), dolomite and some other kinds of rocks. Zircon LA-ICP-MS U-Pb dating results indicate that the gabbro has the age of 496.4±2.2 Ma, indicating that this ophiolite was formed in Late Cambrian. Geochemical characteristics of pillow basalts in the ophiolite mélange show dual nature of ocean floor alkaline basalt (OIB) and middle ocean ridge basalt (MORB); in addition, pillow basalts appear alternately with silicalites. All the evidence suggests that they formed in the deepwater ocean basin. Regional geological analyses indicate that the Baiyunshan ophiolite mèlange represents a relic of early Paleozoic middle ocean ridge.