The electric field and the stress induced strain and polarization responses of [0 0 1], [0 1 1] and [ 1 1 1] oriented Pb(Mg Nb-1/3(2/) (3))O-3-0.32PbTiO(3) (PMN-0.32PT) relaxor ferroelectric single crystals have been systematically investigated by experimental study. The responses of [0 0 1] oriented single crystal to stress cycle and electric field are explained by polarization rotation and phase transformations mechanism. However, the responses of [0 1 1]and [1 1 1] oriented single crystal should be explained by domain switching. The differences of strain and polarization between the minimum and maximal values of electric field in [0 0 1] orientation firstly increase then decrease with enhancing of compressive stress. (c) 2005 Elsevier Ltd. All rights reserved.