A series of Si-doped Bi_3.79Er_0.03Yb_0.18Ti_2.97W_0.03O₁₂∶xSi phosphors were prepared by high temperature solid-state sintering, and their structures and upconversion fluorescence properties were explored. The experimental and test results show that the Bi_3.79Er_0.03Yb_0.18Ti_2.97W_0.03O₁₂∶xSi phosphors prepared in different atmospheres are Bi₄Ti₃O₁₂ phase with single layered perovskite like structure. Si is mainly Si⁴⁺ in the phosphor, indicating that even in the argon atmosphere, most of the doped Si is oxidized. Si doping increases the density and surface smoothness of the material, reduces the optical band gap and enhances the light absorption. Under 980 nm infrared light excitation, the upconversion emission spectra of all samples show three emission bands centered at 525 nm, 545 nm, and 765 nm, respectively, corresponding to the electronic transitions in the Er³⁺4f electron layer. The luminescence intensity and fluorescence lifetime of the sample doped with 6% Si mole fraction are about twice as that of the sample without doping Si, indicating that Si doping can significantly improve the photoluminescence performance of rare earth doped bismuth titanate based phosphors