We have investigated radiation-induced segregation (RIS) near a grain boundary in an austenitic stainless steel under electron irradiation taking into account the simultaneous evolution of faulted dislocation loops and network dislocations by a composite model. It has been found that dislocation free zones (DLFZ) formed in the vicinity of the grain boundary by the irradiation, and we carried out direct observation of the DLFZ formation by in-situ irradiation in a high-voltage electron microscope (HVEM). Prediction of temperature and dose dependence of DLFZ formation agreed with experimental results. The inter-relationship between RIS and DLFZ formation near a grain boundary has been substantially clarified. RIS and DLFZ were understood considering point defect and solute flow associated with the excess defect to the grain boundary.