Abstract: Since the end of the 1990s, the theory that paleovolcanic apparatus can dominate massive sulfide deposit in marine volcanic terrain has attracted more and more attention. Based on this theory, great progress for mineral exploration has been made in the Baiyin orefield located in the eastern part of the North Qilian Mountain. Meanwhile, exploration of the mapping method based on volcanic rock facies has laid the foundation for recognizing the paleovolcanic edifices and mineral exploration. Thus, it should be very important to employ reasonable methods for mapping in the marine volcanic terrain. In this paper, firstly the authors analyzed the paleovolcanic apparatus of the Baiyin orefield and introduced the achievement of large-scale mapping. Then, based on an analysis of the successful case, the authors summed up the contents and methods for mapping in the marine volcanic terrain. At last, guided by the method, the authors provided two successful examples of mapping work in the region near the Qilian County, which is located in the middle part of the North Qilian Mountain.