The distribution of metal elements, oxygen isotopic, composition, variation of ore grades and horizontal zoning of the porphyry bodies, all indicate that the source of ore-forming materials of the Dexing porphyry copper deposits mainly came from intermediate-acid magmas. The existence of a ring-shaped low-copper-value region outside the ore district about 2~5 km across and 115 km2, in area merely indicates that ore materials in near-surface wall rocks were remobilized to some extent and provided a very small percentage of ore metals for the formation of the porphyry deposits, which finally participated in fluid mixing and mineralization when they were driven and heated by intermediate-acid magmas.