The fruit impedance is related to fruit internal quality. Differences in impedance of various quality of apples were measured by use of solartron 1294 impedance interface and solartron 1260 impedance analyzer instrument, four brass-wire probes electrodes, personal computer and the software of bioimpedance measurement of fruits. Apples as examples were experimented at frequency range (1 Hz ~ 1M Hz), and the relation between their impedance parameters and their quality was studied. The results of experiment indicate that the increasing of the frequency could constantly lead to the decreasing of the impedance. When the frequency was increased from 1Hz to 1MHz, the two points impedance of apples' surface decreased 12-15 times. The impedance of good quality apples was nearly constant at both low and high frequency. When detected the rot apples, the impedance was similar to the good apples' at high frequency, and different at low frequency. It was 60-100 ohm lower than normal for the rot apple detection of various rot area. At 1Hz frequency, the impedance measured of 10cm2 rot area was 397ohm, which was about 200ohm lower than normal. The conclusion is it feasible that the bioimpedance can be adopted to distinguishing the internal quality of fruit.