Spontaneous fluorescence, as a kind of life information, can reflect cellular metabolism and DNA synthesis, so it plays an important role in evaluation of drought resistance during germination of crop seeds. To establish the method of drought resistance evaluation based on spontaneous fluorescence in germinating stage of maize, change of spontaneous fluorescence was studied in Wanrui No. 168 and Yandan No. 8 under water stress induced by PEG-6000 solution with the osmotic potential of －0.1 MPa and －0.3 MPa. The results show that spontaneous fluorescence of the two cultivars increase with the germination process, while is inhibited by water stress. The inhibition effect of spontaneous fluorescence to Wanrui No. 168 is more obvious than that to Yandan No. 8 under the same intensity of water stress, and the higher the intensity is, the greater the interspecific difference will be. It is also found that relative change rate of spontaneous fluorescence named RSL during germination of seeds can reflect the dynamic process sensitively of response, adaptation and damage to water stress in life activities of seeds, and it is nondestructive and sensitive using RSL to evaluate drought resistance in germination period of maize.