Abstract: In order to study mineralogical characteristics of skarns in the Jiama copper polymetallic deposit and further identify genetic type of this ore deposit, this paper has studied such skarn minerals as garnet, augite and wollastonite by means of electron microprobe analysis and microscopic examination. The results show that garnets in the ore deposit are mainly andradite-grossularite and augites are mainly diopside. The skarns in the Jiama ore deposit belong to typical calcic skarns. Based on previous researches on the geochemistry of skarns, wall rocks, granite and on geochronology, this paper has revealed the genetic mechanism of the Jiama copper polymetallic deposit. Mineralization was closely related to the granites and the ore deposit resulted from the replacement of the marble by granitoid magma. The Jiama ore deposit is a typical skarn deposit.