ObjectiveTo identify Brn-3a is a reliable endogenous marker of RGCs by contrast with Thy-1.1 expression of the characteristics and differences count in rats.Methods20 health adult SD rats were divided into two groups, one eye was selected randomly for group of Thy-1.1, at the other as group of Brn-3a in the same rat.Morphological structure was investigated by haematotoxylin-eosine staining of retinal paraflin section respectively.Expression of Brn-3a and Thy-1.1 was measured by immunohistochemical method.RGCs were counted by immunolabelled cells.ResultsThere are ganglion cell layer(GCL), inner nuclear layer(INL) and outer nuclear layer(ONL) in retina of rat.GCL was monolayer, alignment rarefaction.Brn-3a+ cells were only present in the GCL and showed a spatial distribution comparable to that of Thy-1.1+ cells: the Brn-3a signal was located in the nuclei, and the Thy-1.1 signal was major in the cytoplasm.There was no significant difference between the numbers of RCGs by labeling of these two markers in the same area.There was a significant difference among in the numbers of RCGs by labeling of these two markers in the different area.ConclusionBrn-3a can be used as a reliable marker to identify and quantify RGCs.