This paper presents the study on ERG in 50 normal eyes. It is to record the retinal response to single light stimulation after dark adaptation. Dual-Trace Oscilloscope Model VC-8 of Nihonkoden, Lovac Type Contact Lens of Nihon Contact Lens Co. was used. The results after dark adaptation for 15 minutes (photopic ERG Fig. 5) show that (1) α-wave varies from 100 to 250 μV, the average being 172.89 μV (2) b-wave varies from 200 to 642 μV and the average is 297.81 μV; and after dark adaptation for 30 minutes (scotopic ERG Fig. 6) show that (1) α-wave varies from 100 to 276 μV, with average of 204.21 μV (2) b-wave varies from 210 to 858 μV and the average is 434.77 μV. In all the b-wave, we can see the oscillatory potential in their ascending limbs. The other components of ERG, such as ERP, c-wave, d-wave etc. and the subcomponents are not discussed. They remain for further evaluation.