Objective To investigate the survivability of ret inal ganglion cells (RGC) after optic nerve crush with intraocular injection of schwann cells(SC) derived neurotrophic (SCNA) in vivo． Methods Schwann cells of 3～5 day newborn mice were cultured,conditioned media without serum was collected,ultraspeed centrifugalized,and frozen-dry.SD rats were divided into normal contrl,crush control,medium treatment and SCNA treatment groups,and 20 eyes in every group.RGC of adult rats were labelled with flu orogold.Seven days later,the optic nerve was intraorbitally crushed and SCNA was injected into the vitreous on the 5th,7th,21th and 28th day after crush,the number of RGC were counted respectively. Results The densities of RGC began to decrease on the 7th day after injury,the number of RGC was 70.2% and 40.5% of normal controls on the 14th and 28th day,respectively .In the group with SCNA injection,RGC densities decreased on the 7th day,but RGC densities were much higher then that of controls on the 14th,21th,and 28th day after injury (Plt;0.01). Conclusions SCNA administered intraocularly at the time of crush of optic nerve can protect RGC from injury and death of the cells. (Chin J Ocul Fundus Dis，2000，16：1-70)