This paper presents a novel experimental and numerical investigation into ultraviolet-lightinduced multi-physics responses of 0-3 polarized PbLaZrTi (PLZT) plates with transparent indium tin oxide (ITO) electrodes on both surfaces. Part I details the testing set-up, procedure and results for the 0.3 mm thick PLZT sample polarized at room temperature and an electrical field strength of 1200 V mm −1 . The measured time-dependent curves and steady state results are presented for the photo-induced electrical voltage and current, temperature and transverse displacement of a 0-3 polarized PLZT plate with double-sided ITO electrodes. It is worth noting that there exists no report on the measurement of transverse displacements of 0-3 polarized PLZT plates, which plays an important role in validating the novel finite element formulation for their multi-physics fields in part II.