This work proposes a mask design method to change the film thickness distribution for the rotary plane coating machine, and successfully deposits a continuously variable filter. The results indicate that the test spectrum exhibits linear gradient passband filtering characteristics at different positions along the spatial direction. The continuously variable filter operates between 650 and 1050 nm, with the linear dispersion coefficient of 32.92 nm/mm over 12 mm. The peak transmittance of the filter is more than 80%, the transmittance of cutoff band is less than 0.1%, and the half bandwidth of the passband is almost consistent with 1.5% of the central wavelength. These parameter indicators fully meet the design requirements.