To investigate the effects of power voltage, frequency and holding warm time on the activity of lipoxygenase in soymilk, ohmic heating and conventional heating (oil bath heating) for the soymilk were employed. The results showed that by ohmic heating the lipoxygenase activity of soymilk increased with the increasing of voltage; the higher power frequency had a significant effect on the passivation of lipoxygenase; but a little effect on lipoxygenase activity when power frequency exceeded 500 Hz; extending holding warm time and the electric field accelerated the passivation of lipoxygenase. This investigation could have positive instructive effects on the design and production of ohmic heating equipment.