Abstract: Huanglong Cave Site at Yunxi Country in Hubei Province,China,dated about 100 thousand years ago,was excavated three times during 2004 and 2006.Seven teeth of Homo sapiens and many mammal fossils,associated with stone and bone artifacts were uncovered.The materials researched in this article were forty bone fractures that had evident surface modifications obtained at this site.Samples were examined carefully with integrated observing technologies including the use of optic microscope,digital microscope with super-depth of field,and three-dimension scanner.According to the difference of original agents,three kinds of surface modifications were identified,and they were Human oriented modifications(including cutting marks,scraping marks,chopping marks and percussion marks),animal oriented modifications(including tooth marks produced by rodents and carnivores)and taphonomic modifications.The distributions and combinations of all kinds of surface modifications were quantified after observing and identifying process.First,the distributions of Human oriented modifications on three bone elements were quantified,and three bone elements were upper limb bones(referring all the bones on the animals' four limbs except the metapodials),axial bones(referring skulls,vertebras and ribs)and unidentified bones.Secondly,the distributions of Human oriented modifications on different anatomical sections were quantified.The primary quantifying results were that there were 25 and 10 bone fractures in upper limb bones and axial bones respectively,and there were only 4 bone fractures in unidentified bones.The percentage of cut bone fractures,scraped ones and chopped ones in upper limb bones were 64%,24% and 12% respectively,and the percentage of cut ones,scraped ones and chopped ones in axial bones were 70%,10% and 20% respectively.The two groups of percentages were similar meaning that butchering activities scattered equally on all the bones of animals relatively.More than 70%(table 1)of cutting modifications were on middle shafts that had rich meat resource.There are only 10.3%(table 4)bone fractures that had the combinations Human oriented modifications and animal oriented modification.The researching results supported the conclusion advanced previously by other researchers that bone deposits at Huanglong Cave site were situ ones,and showed that hunting and butchering activities were mainly responsible for the formation of the deposit.Careful butchering work were performed in the cave after the games were obtained in the surrounding areas and concentrated in the cave.Food sharing activities also had been conducted by the dwellers in Huanglong Cave.The butchering actions once conducted by priority were cutting,scraping,chopping and smashing.Large proportion of cut marks were for the defleshing activities,some cut marks on the epiphysis sections and most chopping marks were the results of carcass disassembling,and the percussion marks were involved in marrow eating and bone artifacts manufacturing activities.In addition,animal oriented modifications associated with the Human oriented modifications reflected that carnivores and rodents also made use of some of the bone assemblage.