The thermodynamic property of eutectic liquid in cold plate was analyzed in this paper．A mathematical model has been set up to predict the melting process of cold plate. The melting processes of cold plate with NaCl at ﹣30 ℃ initial temperature were calculated by using numerical method under three environmental temperatures such as ﹣10 ℃

0 ℃ and 10 ℃. The related experiments were also carried out and the accuracy of the simulation results was verified by the experimental results. The melting process and characteristics of cold plate were obtained under different environmental conditions. The results shows that when environmental temperature is above the eutectic point ﹣21.2 ℃

the environmental temperature will have a great influence on the duration of the melting time as well as the moment for the eutectic to occur phase transition. The computational results are in good agreement with experimental ones. The average deviation of experimental data and computational result is less than 0.5 ℃

which indicates that the mathematical model and the calculating method are reliable.