Abstract: Objective :To study the diagnosis and differential diagnosis of prinitive neurotodermal turnor(PNET)of the bone and soft tissue. Met-hods :All cases were examined using immunohistochemdical and light microscopic method results the pathological morphology of the tumor ch-aracterized by the Presence of Homer-Wright rosettes,lobular structure is sepelated by connective tissue,a litter glycogon in tumor cells,and /or the expressions of at least two neural markers. Conclusion :PNET should be distinguished from other small cell tumor using immunohistochemical method befor making its diagnosis.