Anisotropic domain switching paths in [001]-, [011]-, and [111]-poled Pb(Mg1/3Nb2/3)O-3-0.30PbTiO(3) single crystals were studied by in situ polarized light microscopic driven by an antiparallel electric field. Orientation-dependent electric field induced polarization and strain behaviors were investigated systematically. For [001]-oriented crystals, only one-step 71 degrees switching occurred during the domain switching process, resulting in the appearance of stripe domain walls whose traces on (001) plane were along 45 degrees or 135 degrees with respect to [100] direction. But for [011]-oriented samples, a two-step 71 degrees switching was observed during 109 degrees switching and the projections of formed twin domain walls on the (011) plane are along 35.3 degrees or 144.7 degrees with respect to [011] direction. Moreover, a three-step 71 degrees switching was found during 180 degrees switching in [111]-oriented samples. It was demonstrated by the produced domain walls whose projections on the (110) plane are along 35.3 degrees, 90 degrees or 160.6 degrees with respect to [11] direction. The energetically motivated mechanism based on multistep polarization switching process was also proposed to explain the anisotropic domain switching paths. Our results provided a visualized observation on the ferroelectric domain switching process and also laid the solid foundations for controlling polarization order parameter in ferroelectric single crystals.