Abstract: Abundant benthic foraminiferas, identified mainly as Nodosaria, Pachyphloia and Langella, were discovered in the muddy limestone of the Qixia Formation in Yanmenkou area, Jingshan County, Hubei Province. Most of the foraminiferas chamber were filled by pyrite framboids. Systematic microscopic, scanning electron microscopic observations and energy spectrum analysis of pyrite were carried out. The maximum diameter of pyrite framboids is 15 μm, and the average is about 10 μm. The sulfur to iron atom ratio (S/Fe) is 1.90 ± 0.10. All these features indicate that these chamber were formed under a weak to moderate dysoxic micro-environments. Based on the discussion of the formation mechanisms of pyrite framboids, it is thought that these pyrite framboids in foraminiferas chamber have restricted significance in the study of deposition and diagenesis environment.