<p>To investigate the improving effect of magnetic field-assisted osmotic dehydration pretreatment on the quality of frozen strawberries, this study evaluated its influence on the color, key enzyme activities, and antioxidant properties of the fruit. The results showed that magnetic field-assisted pretreatment significantly increased the <i>a</i>* value of frozen strawberries and effectively inhibited the activities of peroxidase, catalase, and superoxide dismutase. Compared with direct freezing treatment, magnetic field-assisted permeation dehydration method resulted in a 52.47% increase in the retention of total phenolic substances, 42.10% increase in total flavonoid substances, and 57.65% increase in total anthocyanin substances in frozen strawberries. The correlation analysis indicates that the color (<i>a</i>* value) is positively correlated with the activities of polyphenol oxidase, catalase, and superoxide dismutase enzymes and the antioxidant capacity. Principal component analysis further confirmed that magnetic field-assisted osmotic dehydration pretreatment helps to better preserve the nutritional quality of strawberries. Therefore, magnetic field-assisted osmotic dehydration pretreatment is an effective method for improving the quality of frozen strawberries.</p>