Abstract: With the water chestnut wet starch as the experimental object, the effects of water content and quality changes were studied in three different microwave power conditions. The results indicate that the drying curves of the water chestnut starch show the characteristic of the fruits and vegetables typical drying curve.The water content decreases with the increasing of the drying time, the white degree and acidity of the water chestnut show a rising trend with the increase of microwave drying time, while the iodine blue value decreases and then increases.The viscosity decreases.Under the certain range of microwave drying power, with the power smaller, the drying rate is more slowly, acidity is lower, iodine blue value and viscosity are bigger, whiteness has no significant change.