Potato tuber worm Phthorimaea operculella Zeller (Lep.: Gelechiidae) is one of the most important and destructive potato pests in the fields particularly in the warehouses of the world. The effect of four different potato cultivars including (Agria, Impala, Satina and Sprint) on digestive enzymes activity of potato tuber moth were studied in the laboratory condition at 25 ± 1 ° C and 60 ± 5% RH, and 10: 14 hours (L:D) . To determine the state of digestive physiology in the potato tuber worm, the gut tract of the last instar larvae was prepared for enzymatic studies. The results of this study showed that there is no significant differences among potato cultivars regarding the protein content and serine protease activity, so the amount of protein in the enzymatic gut extract of larvae which fed on Agria, Impala, Satina and Sprint was 2.746, 3.54, 2.749, and 3.614 mg/ml, respectively. The level of serine proteinase on mentioned four cultivars was obtained 0.0174, 0.125, 0.0189 and 0.129 (U/mg), respectively. In addition, there was significant difference in terms of relative amylolytic and activity alpha-amylase activity in optimum pH among four potato cultivars. The relative amylase activity was obtained 7.80, 29.10, 14.06 and 12.10 on Agria, Impalana, Satina and Sprint (%), respectively. The most alpha-amylase activity were found in the digestive tract of larvae which fed on Agria (0.103 U/mg) and Impala (0.102 U/mg) cultivars. The results of the current study showed that the amylase activity was higher than protease activity on four potato cultivars.