In order to achieve the imaging resolution of 45 nm with a numerical aperture of 1.35 and a wavelength of 193 nm in the lithography exposure system of ultra-large scale integrated circuits, a novel optical variable attenuator is designed. The device cannot only control the light transmittance, but also adjust the exposure energy. The average transmittance of the attenuation surface decreases from 95% to 8% linearly when the light incidence angle changes from 20° to 40° , and light energy loss of the other three faces are less than 1% in this system. Optical films are designed and fabricated with fused silica as substrate, and LaF3 as well as AlF3 as optical films. Experiments are performed to investigate the attenuator performance, and the results show that the light transmittance is continuously tunable in the range from 8% to 90%, which satisfies the requirements of the system. Compared with traditional optical variable attenuators, the device is with wider attenuation modulation range and more stable attenuation, and it has potential applications.