The Yindonggou silver polymetallic ore deposit is a typical vein-like collision orogenic type, which occurs in the Pzler Formation of Early Paleozoic in the North Qinling fold belt. It is a major breakthrough in prospecting of the Pzler terrane with a large or extremely large scale. Metallic minerals consist of independent minerals such as silver-gold argentite and sulfide, with a coexisting relationship of sliver, lead and zinc. By analysis of geological and geochemical characteristics, the mineralization mechanism of this deposit is explored in this paper. It suggested that the ore-forming materials of the deposit stemmed from strata of the Xiaozhai Formation superimposed by the Songduo granite magma, and ore-forming thermal fluids came from metamorphic water mixed partially with magma water and hot brine. The mineralization occurred at intermediate temperature. And the deposit has been obviously reformed by the collisional orogen.