The invention relates to the field of large-scale equipment transportation and storage, in particular to a safe unloading method for an integral cold box of a large-scale air separation device. The method is characterized by comprising the following steps that 1, field investigation is carried out and a scheme is determined; 2, the foundation of a storage area of the integral cold box is processedto be flat; 3, positioning paying off of support points and foundation pre-pressing observation are carried out; 4, cold box storage supports are placed in place; 5, the integral cold box unloading and leveling are carried out; 6, a simple settlement monitoring device is arranged; and 7, process settlement monitoring and adjustment are carried out. According to the safe unloading method for the integral cold box of the large-scale air separation device, the integral balance of the cold box is adjusted through the special storage supports of the integral cold box, and meanwhile, load force requirements of the foundations of the supports are reduced through force transmission of the supports, and the simple settlement monitoring device composed of tapes and weight blocks is matched, so thatthe balance state during storage of the integral cold box is mastered at all times, and the storage safety of the large-scale integral cold box is ensured.