The change of dynamic viscoelastic properties of liquid crystals was monitored using the quartz crystal resonator by measuring the resonant frequency and the resonant resistance of the quartz crystal during impression of voltage pulses. The viscoelastic change showed different responses as the effects of the applied voltage amplitude, an alignment film and the anisotropy of dielectricity. The higher applied voltage and a cell with alignment films gave larger responses than lower applied voltage and a cell without alignment film, respectively, and the positive and negative anisotropy of dielectricity gave opposite responses. The diagramed resonant frequency and resonant resistance for the voltage pulses showed hysterisis, and these changes are understood as the hysterisis of the dynamic orientation processes of liquid crystal molecules.