This paper proposes an ultra-narrow band solid state optical filter with Voigt anomalous dispersion at 1530 nm based on Er3+: LiYF4, sets a theoretical model for its realization of ultra-narrow band optical filtering, and performs simulations based on the model. The results show that the maxi-mum transmission of the filter is close to 80%, while the line-width is only in the order of 100 MHz, while its transmission peak can be tuned flexibly by adjusting the magnetic field. This filter has a natural advantage in space laser communications, which is another promising ultra-narrow band optical filter.