The invention relates to a low-temperature electrolyte of a lithium iron phosphate battery. The low-temperature electrolyte includes the following solvents of, by volume, 30%-45% of carbonic ester solvent, 50%-65% of carboxylic ester solvent and 4%-10% of additive. The solvents contain solute lithium, the lithium is LiPF6 or a combination of the LiPF6 and LiBF4, and the concentration of the lithium is 0.8-1.4mol/L. The low-temperature electrolyte is a nonaqueous electrolyte, through optimization of kinds and proportioning combination of the solvents of the electrolyte, low-viscosity carbonic ester and low-melting-point carboxylic ester are selected and used, the freezing point at low temperature is lowered, and low-temperature conductivity is increased. According to the low-temperature electrolyte, the lithium of the electrolyte is optimized, the low-temperature additive is selected preferably, normal-temperature circulation ratio performance of the electrolyte is maintained, and meanwhile, the low-temperature capacity retention ratio of the lithium iron phosphate battery and the ratio performance of the lithium iron phosphate battery are improved. The commercial application requirements of the electrolyte can be met, the low-temperature performance of the electrolyte is improved particularly, and therefore the electrolyte is suitable for aerospace and plateau alpine environment.