Erze karst-type gold deposit of Muli, Sichuan, discovered in the western margin of Sichuan-Yunnan metallogenic belt, is tectonically located in the transitional belt between Songpan-Gauze fold system and Yangtze paraplateform.The deposit occurs in the Upper Permian marine carbonate formation. The occurence of orebodies is strictly restricted within the Palaeokarst. The orebodies,which have complex morphology and sharp boundaries with enclosing rocks, are generally in sack-like, with rising and falling roof as well as bottom commonly developing “fibrous roots". Siderite is the dominant ore mineral, of which about 90percent of an orebody is composed, with minor quartz and pyrite. Native gold,and, secondly, electrum occur in the siderite bodies unevenly.It shows that the origin of the deposit is associated with a meteoric hydrothermal convection system. Two successive stages of ore-forming process are distinguished:the early one followed by the middle-late one. Temperatures range between 156 and 210℃, and depth is less than 1 km. It is suggested that the carbonate formation is the source bed.The solution is charaterized by alkli, weak in reduction, poor in sulfur, and medium salinity. It is interpreted that during the mineralization the tectonic environment is relatively stable, both gentle uplift and ground water convection are the necessary conditions for the karst development which created the best room for migrating solution and ore deposition; after the gold-siderite ore formation deposit formed. It was strongly suffered from weathering, leading to the widespread development of secondary oxide and the further enrichment of gold.It is a rather unusual and very important gold-deposit type, found only in our country so far. Obviously, it is necessary to study it more in detail.