The low half-wave voltage electro-optic modulator is crucial for achieving large-scale photonic integration. This article proposes a thin film lithium niobate Mach-Zehnder electro-optic modulator with a half-wave voltage below 1.5V. The design is based on a single crystal thin film lithium niobate material on an insulator. The influence of the straight waveguide, multimode interference coupler, bent waveguide, and modulation arm on the electro-optic modulator is analyzed. The results show that when the length of the modulation arm is 3mm, this thin film lithium niobate electro-optic modulator has a low half-wave voltage of 1.05V, a low loss of 0.319dB, and a high extinction ratio of 27dB. At the same time, the modulator has a half-wave voltage-length product of 0.315V·cm, high modulation efficiency, and a half-wave voltage compatible with CMOS technology, which is beneficial for large-scale photonic integration.