With the aim to investigate the effect of postharvest dehydration on dielectric properties of grape during cold storage, the dielectric parameters of the Red Globe grape were measured at 0.1kHz，1kHz，10kHz，100kHz and 1MHz by using LCR electronic measure instrument, and the results were compared with those of un-dehydrated grape under the same condition. For the un-dehydrated and dehydrated grapes, both of them have the same trends at same storage day: the impedance, reactance, inductance and resistance were all gradually decreased while the susceptance increased with the increase of the frequency; and the loss tangent, dielectric constant and impendence phase angle firstly decreased with the frequency increasing from 0.1kHz to 100kHz, and then increased at 1MHz. Compared with the un-dehydrated grape, the dehydrated one has higher impedance, reactance, inductance, resistance and lower dielectric constant, impendence phase angle during 45 days storage. All the test results show that postharvest dehydration is a more effective way in keeping the quality of grape during cold storage. 