Gongchangling iron deposit is a typical deposit of Anshan-type sedimentary-metamorphic iron deposits. how the high-grade iron body formed is focus on,According to research, the high-grade iron bodies is in the anti-s fold. the high-grade iron bodies are in the rocks composed of plagioclase-hornblende,magnetite-quartzite.The wall-rock of high-grade iron bodies are chlorite schist, garnet-chlorite schist, chlorite-garnet and a little biotite-chlorite schist.By analyzing the iron content of chlorite,garnet and biotite and analyzing the main elements,trace elements,REE of chlorite schist,granet-chlorite schist and chlorite-garnet, the results show that the aluminum-containing pelite - aleurolite between the magnetite-quartzite is an important factor for formating high-grade iron bodies,it can absorb quartz in the magnetite-quartzite and form chlorite,garnet and biotite. the regional metamorphism is the critical condition for forming high-grade iron bodies. On the one hand ,the regional metamorphism can form space for ore and hydrothermal fluid and the power of the hydrothermal fluid migration which could bring out the FeO from the magnetite-quartzite. On the other hand, the regional metamorphism can provided the necessary temperature and pressure conditions for the minerals transforming.