The digital image correlation technique is used for full field measurements of axial strain and transverse strain of PZT95/5 ferroelectric ceramics under uniaxial compression. Based on the variations of the axial strain and transverse strain with axial stress, the effects of poling state and poling direction of PZT95/5 ferroelectric ceramics on the domain switching and phase transformation behaviors are explored. Domain switching occurs in unpoled and Z-axis poled PZT95/5 ferroelectric ceramics separately, while domain switching in the Y-axis poled PZT95/5 ferroelectric ceramic is not observed. Domain switching strain in the Z-axis poled PZT95/5 ferroelectric ceramic has obvious influences on the developments of axial strain and transverse strain, but the influence of domain switching strain in the unpoled PZT95/5 ferroelectric ceramic is very weak, which can be attributed to the different random distribution characteristics of domain orientation. By the strain decomposition analysis, it is proved that the domain switching and the phase transition process can be decoupled, and domain switching strain and phase transformation strain can be distinguished successfully. Compared with the Z-axis poled PZT95/5 ferroelectric ceramic, the unpoled PZT95/5 ferroelectric ceramic has a small critical stress of phase transformation, while the critical stress of the Y-axis poled PZT95/5 ferroelectric ceramics is big, which may be concluded that the domain switching behavior favors the phase transformation process. The polarization released behavior of PZT95/5 ferroelectric ceramic also depends on the poling direction. The depolarization mechanism of Z-axis poled PZT95/5 ferroelectric ceramic is caused by both domain switching and phase transformation, and the Y-axis poled PZT95/5 ferroelectric ceramic is caused by only phase transformation.