Abstract:The silver grade of an associated silver deposit is 89.2g/t. In order to determine the silver occurrence state, the systemic research is carried out with instruments such as optical microscope and large advanced MLA. The result shows that the silver in the ore mainly exists in three kinds independent minerals; argentite, naumannite and aguilarite respectively; and the distribution ratio of the silver in those minerals are 53.42%, 44.26% and 2.31% respectively; and the silver mineral grains which are small than 0.020mm are mostly wrapped up by mica minerals and only a small part of the silver mineral grains are wrapped up by dolomite, quartz or barite. So，insufficient liberation of silver minerals and the rejection of dolomite by reverse flotation will cause silver losing in the tail.