Studying if there took place extensive exhalative-sedimentary activities in the southeast Yunnan Province has been one of key factors to constrain origin of the Gejiu, Bainiuchang, and Dulong polymetallic deposits. The authors systematically study the geochemistry characteristics of host-rocks in the Bainiuchang Ag- polymetallic deposit in this paper. The host-rocks have the same distribution area with the sea-floor volcano or hot-water origin chert.