Y4Si2O7N2: Eu2+ phosphor has been prepared by a pretreatment method. Reduction in Eu3+ ions into Eu2+ by the use of hydrogen iodide (HI) is verified by X-ray absorption near-edge structure (XANES) and electrode potential analysis. Y4Si2O7N2: Eu2+ phosphor has a broad emission band in the range of 400-500 nm. Furthermore, the effect of Zr doping on the structure and luminescence properties of Y4Si2O7N2: Eu2+ phosphor is researched. It found that the Zr doping leads to an emission blueshift, and improves the luminescence intensity and thermal quenching behavior of Y4Si2O7N2: Eu2+ phosphors. Prospectively, the pretreatment approach could be extended to develop other Eu2+-doped compounds.