The invention relates to a two-section rotation oxygen-enrichment external heating oxidation technology and device for dry-method and semi-dry method desulfurized ash. A two-section type rotation oxidation kiln is adopted, oxygen is introduced into the kiln and heating is implemented by adopting an external heating furnace, so that the oxidizing process for converting CaSO3 in the desulfurized ash into CaSO4 is completed. Compared with the prior art, the technology and the device have the benefits as follows: (1), during the oxidation of the desulfurized ash in the oxidation kiln, stable oxidation time, balanced oxidation temperature, sufficient oxygen content and appropriate oxidation atmosphere are realized, the technical measures such as automatic control, surplus heat utilization, dust removal and environment protection are adopted, so that the low-cost oxidation and industrialized production are realized; (2), the provided systematic desulfurized ash oxidation production line is suitable for the industrialized and large-scale production requirements; (3), the processing parameters such as oxidation temperature, time and oxygen content are controlled through a PC (Personal Computer), so that the appropriate oxidation conditions are ensured; (4), the promotion of the development of a dry-method and semi-dry method desulfuration technology is facilitated; (5), the resource utilization of the desulfurized ash is realized, and the energy conservation, emission reduction and environment protection are facilitated.