The low-frequency electric fields with intensity of 600 V/m，1 500 V/m，and 3 000 V/m were used to solve the problems of difficulty in maintaining the quality of freshwater fish during the traditional process of preservation with partial freezing.The indexes including the loss rate of drip，the capacity of holding water，hardness，color，the content of total volatile basic nitrogen （TVB-N），and the water migration of tilapia fillets preserved by partial freezing were measured to study the effects of electric field-assisted partial freezing on the quality of fillets.The results showed that low-frequency electric field effectively suppressed the loss rate of drip and maintained the capacity of holding water during the storage with partial freezing，with greater intensity resulting in more significant effects.The loss rate of drip in samples treated with 3 000 V/m electric field was significantly lower than that in the control group （P<0.05） from the 4th day，with significantly higher capacity of holding water （P<0.05）.Meanwhile，low-frequency electric field inhibited the deterioration of color，decreased the hardness，increased the content of TVB-N，and extended the shelf life of fillets.The increase in the content of TVB-N in the control group at 16th days was about 1.6-3.0 times that in the groups treated with low-frequency electric field.The results of low field-nuclear magnetic resonance （LF-NMR） analysis showed that the water in tilapia fillets migrated from immobilized water to free water as the time of storage prolonged.Low-frequency electric fields suppressed water migration，and the higher the intensity of electric field，the more significant the effect.Especially，the low-frequency electric field with an intensity of 3 000 V/m had the best effect on maintaining the quality of tilapia fillets under partial freezing.It is indicated that low-frequency electric field-assisted partial freezing is a feasible and effective technique for preserving the quality of tilapia fillets.It will provide a new direction for the improvement on the effect of preserving freshwater fish with partial freezing.