The piezoresponse behavior dependence of the Pb(Mg1/3Nb2/3)O3-30%PbTiO3 single crystal on the vacuum degree has been investigated by scanning force microscopy in the piezoresponse mode under high vacuum. Unusual piezo- response behavior related to the screening charges compensation mechanism is observed on the (111) crystal face. The significant piezoresponse degradation behavior with low piezoresponse signal under high vacuum is attributed to the instability of thepolarization state due to the insufficient compensation of the intrinsic screening charges for the polarization charges in PMN-30%PT single crystal. In contrast, the remarkable domain contrast of the sample at ambient pressure is owing to the dominant surface screening charges deriving from surface adsorption, which plays an important role in determining the stability of the domain behavior and in achieving the optimal properties.