A liquid micro-optical prism based on electrowetting is developed for wide angle beam tracking and steering. The shape of the two liquid interfaces is analyzed, the relationship between contact angle and two voltages is derived, and the deflection of the beam from the system is detected. In the meantime, COMSOL software is employed to analyze the effect of dynamic viscosity on the prism′s response time and stability. The results indicate that the contact angle between the conductive fluid and wall changes, then interface of the immiscible liquids is rendered into plane accordingly when different voltages are applied on the wall. It succeeds in controlling beam tracking and steering as traditional optical prism. Due to electrowetting saturation, the maximum deflection of the liquid prism approaches to 20° (-10°~+10°); If the electrowetting saturation is decreased or even eliminated while ratio of the refractive indexes of two liquids is increased, the ability of deflection of the system will be enhanced largely. To achieve stable performance and stability of the prism, the optimal dynamic viscosity should be 0.03 Pa·s.