Abstract: Abstract：According to the route geological survey along actual geological sections as well as the study of more than 200 agate mineral spots and mineralized spots, the Yixian Formation is divided into five eruption cycles. This paper describes the main features of the agates belonging to body-like secretory type and fracture filling type in Yixian Formation and related cryptovolcanic rocks in Fuxin area. Some conclusions have been reached: The stratabound characteristics of the agates of these two genetic types are obvious; they mainly originated in the eruption cyclesⅠandⅡof Yixian Formation; the agate veins of the fracture filling type is primarily in the NNW-NNE direction; the sequence of favorable ore rock is andesitic melaphyre, related cryptovolcanic clastic rocks, basalt and volcanogene clastic rocks. On such a basis, it is pointed out that the agate of the fracture filling type is the major genetic type in prospecting for agate in the future，and that the key prospecting areas are Zidoutai-Qijiazi and Laohetu-Shijiazi.