As the beginning of the plant life process, seed germination directly affects the final crop yield. Low-temperature frequently inhibit seed germination, posing a serious threat to food production safety. The effects of low-temperature on the germination of grain seeds (quinoa, highland barley, rice, and wheat) were investigated in this paper using Fourier transform infrared spectroscopy combined with curve-fitting. The results showed that the germination potential, germination rate, and germination index of the four grain seeds decreased as the temperature decreased, but the germination rate and germination index of highland barley seeds remained high at 4 ℃, indicating that highland barley seeds had stronger low-temperature tolerance. The results of infrared spectrum demonstrated that the original infrared spectra of grain seeds under low-temperature were similar, mainly composed of the characteristic absorption peaks of polysaccharide, fat, and protein. Under low-temperature stress, the curve fitting analysis for polysaccharide (1200-950 cm^-1) and amide Ⅰ band (1700-1600 cm^-1) in quinoa seeds revealed that polysaccharide content increased while protein content decreased. The polysaccharide and protein content of highland barley seeds increased at first, then decreased. The content of polysaccharide in rice seed decreased, while the content of protein increased. The polysaccharide content of wheat seeds increased first and then decreased, while the protein content decreased first and then increased. Furthermore, under low-temperature stress, different proportions of protein secondary structures in quinoa, highland barley, rice, and wheat seeds changed from disorder to order. As a result, Fourier transforms infrared spectroscopy combined with curve fitting is an efficient method for investigating the effect of low-temperature stress on seed germination.