In order to study the dynamic change mechanism of droplet dynamic contact behavior under electrowetting conditions, the dynamic contact angle theory is used to establish a numerical model of droplet under electrowetting and the droplet transient behaviour is analysed. In particular, the effects of volume and wall conditions on the dynamic behaviour of droplet are systematically investigated. The results show that the maximum amplitude of the droplet contact radius increases from 0.16 mm to 0.23 mm when the droplet volume increases from 2 μL to 6 μL, and the amplitude increases from 0.13 mm to 0.18 mm when the initial droplet angle increases from 100° to 115°. At the same time, with the slip length from 0.5 μm increased to 2 μm, the maximum amplitude increases from 0.21 mm to 0.29 mm. The larger the droplet volume, the smaller the wall resistance, the stronger the hydrophobicity, and the higher the kinetic energy and the greater the oscillation amplitude of the droplet. By revealing the dynamic contact behavior mechanism of droplets in the process of electrowetting, a theoretical basis is provided for the study of improving the heat transfer characteristics of microchannels through the electrowetting effect.