The invention discloses an analysis method of a cold energy air separation unit. The method comprises the following steps: establishing a three-dimensional solid finite element model of the cold energy air separation unit; analyzing a transient temperature field during the operation of the unit; analyzing the thermal load coupling condition of the unit; and performing heat engine fatigue analysis on the unit. According to the analysis method of the cold energy air separation unit provided by the invention, by performing finite element modeling on the unit, analyzing the transient temperature field distribution of the unit under low temperature conditions, taking the transient temperature field distribution as an influence factor, and analyzing the thermal load coupling condition of the unit, the structural stress of the unit and the occurrence of rubbing can be evaluated, and combined with a thermal load coupling analysis result, the thermal fatigue condition of the unit can be evaluated.