Objective  To study the effect of the duration of dark adaptation on electroretinography （ERG） in SD rats； to develop standardized research programs so results can easily be compared between different laboratories. Methods  In an experimental study， 42 SD rats （42 eyes） were randomly divided into 7 groups based on the duration of dark adaptation： 15 min， 30 min， 1 h， 4-6 h， 12-14 h， 15-17 h， and 24-26 h. Visual electrophysiology recordings were then taken. ANOVA was used to analyze the differences among the groups and a post hoc analysis was used to compare the difference between any two groups. Results  Different dark adaptation durations mainly affected the latencies of the dark-adapted ERG a-wave and b-wave of the rats′ ERG. The latency of 15 min dark adaption time was delayed longer compared with other dark adaption time group （P<0.05）. There was no significant effect when dark adaptation time was longer than 30 minutes. Conclusion  Dark adaptation durations impact ERG recordings. The minimum dark adaptation time for rat electroretinography recording is 30 minutes.