Sn3B10O17Cl2 was successfully obtained for the first time under the sealed environment and crystallized in the space group Pbcn belonging to the orthorhombic system, which is featured by the fundamental building blocks [B5O11] that are linked to construct a three-dimensional framework with Cl and Sn atoms located inside and at the edge of the channel to balance the charge. Moreover, the optical performance measurement shows that Sn3B10O17Cl2 owns a cutoff edge of about 280 nm. Theoretical study indicates its large optical anisotropy with the birefringence 0.125@546 nm; meanwhile, the structure-performance relationships were analyzed by the first-principle calculation.