High-efficiency and ultralow-power electro-optic tuning devices are key components in photonic integrated circuits. Silicon photonic technology is considered to be promising for large-scale and low-cost integration. However, silicon does not exhibit any Pockels effect, and the electro-optic tuning based on free-carrier dispersion suffers from challenges such as high power consumption, and large optical propagation loss. Here, a new hybrid lithium tantalite-silicon platform is proposed for ultra-low-power electro-optic tuning based on the Pockels effect. Benefitting from the strong Pockels coefficients of lithium tantalite thin film, an EO tunable lithium tantalite-silicon hybrid microring is demonstrated. The quality factor and extinction ratio are 17000 and 10 dB, respectively. The linear bidirectional wavelength tuning efficiency is measured as 12.8 pm/V. The proposed platform extends the toolbox of silicon photonics technology, which pave a way for high-speed modulators and phase shifters in optical communication and optical phased array.