Thin-film lithium niobate electro-optical modulator will become the key device in the future optical communication, which has the advantages of high modulation rate, low half-wave voltage, large bandwidth, and easy integration compared with conventional bulk lithium niobate modulator. However, because the electrode gap of the lithium niobate film modulator is very narrow, when the microwave frequency gets higher, it leads to higher microwave loss, and the electro-optical performance of the modulator will be greatly reduced. Here, we propose a thin film lithium niobate electro-optic modulator with a bimetallic layer electrode structure to achieve microwave loss less than 8 dB/cm in the range of 200 GHz, exhibiting a voltage-length product of 1.1 V?cm and a 3 dB electro-optic bandwidth greater than 160 GHz. High-speed data transmission test has been performed, showing good performance.