Abstract: The egg luminescence in storage is studied with a detection system of superweak bioluminescence. The results show that egg has the biggest viability in the third day after laying, subsequently decays with oscillation. These eggs, which have been stored for 3 days, are most suitable to be used for hatching. After researching on the delayed bioluminescence of eggs, the results show that egg luminescence generally obeys hyperbolic decay law, which supports coherence theory of biophoton. Different eggs have different luminescence intensity; it depends on the vital force of the eggs. The stronger the vital force of the egg is, the more intensive the luminescence is. Superweak bioluminescence as a colligate index of biological and biochemistry response can be used for inspecting the fresh degree of the eggs. This method is simple, nondestructive and sensitive. It can not only be used to detect the fresh degree of the eggs, but also to detect the relationship between eggs status and circumstance such as illumination and temperature, which is hard by using other methods.