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In order to study the electromechanical characteristics of PZT-5H in the temperature range of -40~25℃under the impact loading, the electrostatic parameters of PZT-5H at different temperatures are measured, the liquid nitrogen cooling/Hopkinson mechanical property and piezoelectric ceramic voltage output testing system are built, Hopkinson experiments at different temperatures (-40℃, -25℃, -10℃, 0℃ and 25℃) and different impact velocities are carried out. Experimental results show that , the resistivity and relative permittivity decrease with the temperature of PZT-5H decreasing from 25℃ to -40℃, and the relative permittivity decrease about 27.92%, and the relaxation time is also deduced. By scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS) observation, it is found that the blowhole defects and cracks of the piezoelectric ceramics have obvious effects on the electrical output characteristics of piezoelectric ceramics when the piezoelectric ceramics are struck. Based on the analysis of space charge theory, the freezing effect of piezoelectric ceramics caused by the obstruction of domain motion at low temperature is obtained. And the dynamic piezoelectric constant in the elastic region measured is about 1.66 times that of the static piezoelectric constant, which indicates that the relative dielectric constant of the piezoelectric ceramic has changed significantly under dynamic loading.