Silicon-based optical waveguide phase shifters are key components in silicon-based photoelectronic systems. Transparent conductive oxide (TCO) films are expected to be applicable to the next generation of silicon-based optical waveguide phase shifters with high modulation speed, low insertion loss, and CMOS-compatibility due to their tunable permittivity under a gate voltage. However, the high optical absorption coefficient of the TCO has limited their application in electro-optic phase shifters. We propose a compact and low-insertion-loss silicon-based optical waveguide phase shifter based on TCOs with high electron mobility. We demonstrate that the mobility of the TCO material is closely related to their insertion loss. Based on theoretical calculations and numerical simulations, we propose a silicon-based optical waveguide phase shifter based on high-mobility cadmium oxide (CdO, μ=300 cm 2·V -1·s -1) materials. For π-phase shift at 1550 nm, this CdO-based phase shifter shows a low-insertion loss of 1.4 dB, device length of 127 μm, and modulation bandwidth of 300 GHz. It provides a new strategy for the development of high-speed silicon-based optical waveguide phase shifters.