The Yunxi—zaoyang—Suizhou mafic magmatic belt occurs in a NWW trend with length of about 390 km and width of 40~100 km in the northern Hubei Province. Among which there are 14 ultramafic rocks, 21 ultramafic—mafic complex rocks, and 250 mafic rocks, with total outcrop areas of 689 km2. From the second half of the 20th century to the present, the previous investigators unanimously affirmed that all these mafic and ultramafic rocks been originated in magma intrusions along the abyssal fault. The authors selected both the Danjiangkou and the suizhou geological routes at random, and investigated in detail to 35 mafic rock exposures in this years. Based on this research, the authors recognized that the mafic and ultramafic rocks among the whole magmatic belt are not that the liquid magma intruded on the spot, but that a numerous exotic block of mafic rocks emplaced in the turbidite of Wudangshan Group or Suixian Group. In actual fact, there is not so much a zone of mafic magmatite as a largescale m lange belt. The argument of this paper are as follows: (1) The thermal metamorphism is lacking in general for adjoining rocks close the mafic block. The characteristic lamination, stratification and cyclothem of turbidite among the host rock near the exotic blocks still are clearly discernible; (2) The chilled border is absent in common in the margin of exotic blocks; (3) The cumulate bonded structure and facies plane in the gabbroite not depends fundamentally on the shape of mafic blocks, and it frequently cut off by the cintact plane; (4) The gabbro and diabase inside of mafic blocks was injected occasionally by the irregular quartz vein or the plagioclasegranite dike, which of them never intrude into the turbidite round the exotic blocks. There are indications that the times of ultramafic and mafic rocks be earlier than the host rock; (5) Some mafic intrusions with a large or middle scale in this belt generally are not unitary intrusive bodies, but a aggregation of numerous exotic blocks with different scale; (6) The capture of host rocks in interior of mafic blocks is never seen in this investigation. The “captures” which was defined by the predecessors are mostly a turbidite in between the different mafic blocks as the ground mass of m lange; (7) Petrochemical studies of the mafic rocks in the Yunxi—Suizhou belt demonstrate that the said rocks are the tholeiitic magma series, analoguous to the cumulate complex of ophiolite suite.Therefore we may conclude that the Wudangshan—Dawushan region herein lies the above said m lange belt is an accretionary wedge in the southwestern margin of Tongboshan—Dabieshan terrane.