The Wushanding mud volcano is located along the Chishan fault in southwestern Taiwan. Due to the unique tectonic setting, there exist many mud volcanoes along the Gutingkeng anticline and the Chishan fault in southwestern Taiwan. Investigation was conducted on the genesis of the Wushanding volcano. Based on a field investigation of the Wushanding mud volcano, the authors analyzed mineral components, fluid geochemistry and micropalaeontological assemblage of the muddy eructation. The main mineral components include quartz, illite, kaolinite-smetice, illite-smecite, with such fossils as Reticulofenestra minuta and Sphenolithus abies. Fluid ions are composed mainly of Cl-and Na+. It is thought that both the overpressure of the Gutingkeng Formation and the structural extrusion in Quaternary must have played the crucial roles in the formation and activity of the mud volcano.