No. 2 diggings of the Gongchangling iron deposit distributed two types of the richer ores and poorer ores. Around the rich iron body distributed a large number of skarnoid,including garnet rock、chlorine rock、garnet chlorine rock、magnetite actinolite rock.The formation of skarniod and richer ores related to the hydrothermal activity.The trace elements of skarnoid and ores show relatively enriched HFSE and LILE，but relatively depleted Sr and Hf; the skarnoid、poor ores and rich ores have similar PAAS normalized REE patterns，rightist distribution patterns of relative loss LREE with a obvious Eu positive anomaly and weak Ce negative anomaly ,REE and Eu positive anomaly increase regularly from poorer ores、richer ores to skarnoid, which indicate richer ores and skarnoid had inherited REE patterns of poorer ores, and superimposing REE geochemical characteristics of hydrothermal fluid. Combined with field geological features, we favor that the skarnoid and rich ores might be formed by the hydrothermal transformation of poor ores from No. 2 diggings of the Gongchangling iron deposit.