Lithium niobate thin film (TFLN) electro-optic modulators (EOM) are widely used in optical communication systems due to their high bandwidth, low half-wave voltage, and low energy loss. Based on the analysis of the finite element method, we optimize the structure parameters of the modulator and propose an EOM with an S-bend coupler and an electrode gap covered with a SiO₂ layer. The device exhibited a half-wave voltage-length product of 2.13 V · F, a bandwidth greater than 75 GHz, and an optical loss <0.1 dB / cm. Besides, we also propose employing the linear regression algorithm in machine learning to help determine the parameters of high-performance modulators, which provides a new idea for the design and optimization of TFLN modulators.