A mammalian fauna composed of 40 species associated with Xiaogushan Man was unearthed during the archaeological excavations from 1981 to 2007 at Xiaogushan Paleolithic Site,Haicheng,Liaoning Province.The analyses of the fauna and comparison with other related faunas indicate that Xiaogushan fauna is very similar to that of Shanchengzi,Gulongshan and Yushu.It is a typical fauna of Northern Region.Its age is within the middle to late stages of the Late Pleistocene(80-20 ka).Influenced by cold period MIS4,the cold forms appeared in the fauna.Nevertheless the decrease in temperature was not very much and the climate was still a temperate one.The fauna’s environment was generally humid,with large forest,some water areas and grasslands.It is suitable for prehistoric human habitation during temperate seasons with considerable food and water resources.The cold period MIS4 might push prehistoric human southward to temperate areas or stimulate them to develop fire using and making techniques. A mammalian fauna composed of 40 species associated with Xiaogushan Man was unearthed during the archaeological excavations from 1981 to 2007 at Xiaogushan Paleolithic Site, Haicheng, Liaoning Province. The analyzes of the fauna and comparison with other related faunas indicate that Xiaogushan fauna is very similar to that of Shanchengzi, Gulongshan and Yushu. It is a typical fauna of Northern Region. It age is within the middle to late stages of the Late Pleistocene (80-20 ka). Influenced by cold period MIS4, the cold forms appeared in the fauna .Nevertheless the decrease in temperature was not very much and the climate was still a temperate one. The fauna’s environment was generally humid, with large forest, some water areas and grasslands. It is suitable for prehistoric human habitation during temperate seasons with considerable food and water resources. the cold period MIS4 might push prehistoric human southward to temperate areas or stimulate them to develop fire using and making techniques.