Abstract: In order to evaluate the effect of storage condition on the S-ovalbumin formation in egg albumen, four influential factors such as storage temperature, humidity, CO2 concentration and film coating were investigated in this study. And an equivalent egg age prediction model was established with S-ovalbumin content as the variable. The results showed that S-ovalbumin formation positively correlated with the storage temperature, and high temperature could accelerate this formation. S-ovalbumin content was not significantly affected by humidity, and high humidity had only a limited inhibition of the S-ovalbumin formation. Low-concentration CO2 (2.5%) did not inhibit evidently the formation of S-ovalbumin, but high-concentration CO2(≥5.0%) had a significant inhibitory effect. Film coating could significantly inhibit the S-ovalbumin formation. Especially, the oil soluble and mineral oil coating processing had a prominent inhibitory effect. By exponential equation analysis, the prediction model of equivalent egg age was established, which could be used to predict the freshness of commercial shell egg stored in any condition by converting S-ovalbumin content into equivalent egg age at 25℃.