In this study, a phase modulating metasurface based on ITO film is designed. The combination of the ENZ characteristics of ITO and the plasma resonance effect of the upper metal electrode significantly enhances the light-matter interaction. By designing the metal-insulator-metal (MIM) capacitor structure, a phase modulation range of >330° is achieved under the gate voltage -2-5 V. Consequently, the optical phase array and tunable focal length lens are successfully realized. The designed phase modulating metasurface is significant for applications, such as optical detection, imaging, and communication.