Low temperature is one of the major factors which produce adverse effects on maize growth and development in Northeast China. 5-aminolevulinic acid (ALA) can improve the low temperature resistance of crops. The objective of this study was to investigate the physiological mechanism of ALAenhanced lowtemperature resistance in maize seedlings as well as the optimal foliar spraying concentration of ALA. This experiment was conducted with maize cultivar ‘Suiyu 13’ under different concentrations of ALA (0, 10, 20, 30, 40 mg·L^-1), at low temperature of 14 ℃/5 ℃ (day/night) for 48 h. Plant morphological growth, cell membrane stability, antioxidant enzyme activity and osmotic adjustment ability were measured. The results showed that foliar spraying of ALA could promote the growth of seedlings under low temperature stress, protect the structure and function of leaf cell membrane, enhance the ability of the cell to remove reactive oxygen species and improve the ability of osmotic adjustment. Among all treatment concentrations, 20 mg·L^-1 ALA spraying treatment had the best effects. Compared with the control, seedling height, leaf area and fresh (dry) weight increased by 24%, 23%, 26% (23%), the malondialdehyde (MDA) content and relative electrical conductivity decreased by 38% and 45%, SOD activity and POD activity increased by 37% and 66%, soluble protein content and soluble sugar content increased by 50% and 45%, respectively, under the treatment of 20 mg·L^-1 ALA. Therefore, spraying ALA of appropriate concentration can relieve the damage caused by low temperature stress to maize seedlings.