Here, we report a series of Eu³⁺-doped Sr₃SnMO₇ (M = Sn, Si, Ge, Ti, Zr, or Hf) phosphors, which exhibited both photochromism and luminescence switching. Under alternating UV (254 nm) light irradiation and visible light/thermal stimulus, the obtained samples showed a reversible color change from the initial white color to brown. Based on photochromism and red luminescence, the red emission could be effectively modulated. Most interestingly, the Eu³⁺ red emission could be reversibly modulated by alternating UV and visible light/thermal treatment with excellent reproducibility, which can be used as non-destructive optical information write-in and read-out. In the case of the Sr₃SnMO₇ host, the band gap could be clearly changed from 3.64 to 4.41 eV through partial cation substitution, resulting in an evident effect on the photochromism and photoluminescence modulation performance. This provides a new method for tuning the photochromism and photoluminescence modulation properties. These results suggest that Sr₃SnMO₇:Eu³⁺ phosphors with photochromism and luminescence switching properties constitute a class of promising candidates for the development of optical data storage devices. On the basis of their luminescence modulation behavior, a model with non-radiative energy transfer from the luminescent centers to the color center was developed.