The work aims to improve the quality of potato after freezing and thawing and provide theoretical basis for the application of PEF pretreatment in vegetable freezing. The effect of pretreatment methods (pulse electric field and blanching) and thawing methods (room temperature thawing, water thawing and refrigerator thawing) on potato freezing-thawing process and quality was discussed, the physicochemical indicators such as ice crystal nucleation temperature, melting temperature, water loss ratio, color, hardness, etc. were analyzed and the migration of water at different states of samples after freezing and thawing was analyzed by low field nuclear magnetic resonance analyzer. Blanching and PEF (Pulsed Electric Field) pretreatment could significantly reduce the freezing time and increase the ice crystal nucleation temperature. Moreover, the retention time of PEF pretreated samples in the maximum ice crystal formation zone was 26.3% lower than that of the control group. PEF pretreatment and blanching pretreatment could both reduce the water loss of potato after different thawing methods. For room temperature thawing, the water loss ratio of untreated, blanching pretreated and PEF pretreated samples were 24.12%, 17.39% and 15.53% respectively. At the same time, PEF pretreatment and blanching pretreatment could also reduce the color change and hardness change of food during freezing and thawing. PEF pretreatment can improve the quality of potato after freezing and thawing, which provides theoretical reference for the application of PEF in the field of vegetable freezing.