Melnikovite, one of the most important ore minerals in the South China type massive sulfide deposits, was originally a sedimentary product of submarine volcanic hydrothermal fluids and has been annealed remarkably in the subsequent geological history. Based upon microscopic studies on ore textures, the annealing process of melnikovite in these deposits might be divided into three stages: primary crystallization, seriateblastic growth and adjustment of grain boundaries. Ores of these three stages usually occupy positions progressively closer to the Yanshanian intrusives in the above sequence, indicating the predominant role played by the thermal effect of these intrusives on the annealing of melnikovite. Accompanying the recrystallization of sulfides, the annealing process has also resulted in a redistribution of minor elements between melnikovite and pyrite.