In this paper, a linear variable optical filter (LVOF) in the visible spectral region based on TiO₂ and SiO₂ is prepared by combining a multi-target magnetron sputtering coating method with a self-made one-dimensional displacement baffle sample stage. The transmittance spectra are characterized by a spectrophotometer and a hand-operated one-dimensional translation stage. The effects of annealing temperature and time on the LVOF transmission spectrum are primarily evaluated in terms of functional dependency. The results show that the workable spectral range of the LVOF sample is 510-700 nm, and the transmission spectral peaks at different positions on the sample have a consistent linear relationship with the sample position. After vacuum-annealing at 300 ℃ for 1 h, the transmittance of the samples is significantly improved, better than 60%. This indicates that the annealing treatment can significantly improve the performance of the LVOF.