The near-infrared laser with a wavelength of 1.064 μm is one of the main laser sources for laser ranging, free-space optical communication, and space optical remote sensing. Narrowband filters are one of the key components that suppress background light interference. At present, the full widths at half maximum of most filters are several nanometers. An ultra-narrow band-pass filter was designed and fabricated, which had a full width at half maximum of 0.19 nm, a peak transmittance of 70.2%, and a central wavelength of (1064±0.05) nm. Then it was annealed at 100 ℃, 200 ℃, and 300 ℃, respectively, and changes in its surface morphology and spectral characteristics were investigated. The experimental results indicate that the surface of the filter is smooth and annealing has little influence on it. In contrast, the transmission spectrum of the filter undergoes redshift as the annealing temperature rises. When annealed at 100 ℃ for 3 h, the filter experiences a spectral shift of 0.03 nm, which shows that the filter is suitable for space optical systems with limited temperature control.