In order to evaluate drought resistance of wheat seed during germination using bio-photonic technology, treatment to germinating wheat seeds with polyethylene glycol,spontaneous luminescence and delayed luminescence of wheat seed in ultra-weak photon emission during germination under osmotic stress were measured. Through establishment of dynamic equation of delayed luminescence and mathematical fitting, the initial intensity I(0), attenuation parameters β, coherence time τ and integral intensity I (T) of delayed luminescence during germination were obtained. And the state parameters and the order parameter of cell system were constructed according to the significance of delayed luminescence integral intensity and spontaneous luminescence. The expermental results shows that the increases of spontaneous luminescence and integrated intensity of delayed luminescence in ultra-weak photon emission of wheat seed are the stage during germination, the increases of the state parameter and order parameter of cell are the stage, and osmotic stress inhibits these increases. It is suggested that the state parameter and order parameter of cell based on ultra-weak photon emission may be used as physical indicators to evaluate drought resistance of wheat seed during germination.