This paper found the freezing point of multiple secondary refrigerant for immersion chilling and freezing by the experiment. The refrigerant consists of ethanol

sodium chloride and water. The mutual influence of each component as well as glucose and protein as an additive to the freezing point of the mixed solution was analyzed. The results showed that suitable composition of multiple secondary refrigerant used in different temperature range for ICF are as follows: above -20℃: Ethanol concentration 5%~15% and sodium chloride concentration 5%~20%; between -20℃ to -30℃: Ethanol concentration 23%~25% and sodium chloride concentration 14%~18%; between -30℃ to -40℃: Ethanol concentration 37%~40% and sodium chloride concentration 12%~14%; between -40℃ to -46℃: Ethanol concentration 40%~55% and sodium chloride concentration 9%~12%. Sodium chloride reduced the freezing point of ethanol solution and ethanol lowered the freezing point of sodium chloride solution. The saturation of sodium chloride on ethanol solution decreased with the increasing of the ethanol concentration. Aqueous protein reduced 1~2℃ freezing point of mixture solution

but the effect of glucose on freezing point of mixture solution was not obvious.