Traditional solid‐state luminescent materials (e.g., phosphors and microcrystalline glasses) have attracted extensive attention due to their high energy efficiency and long lifespan. However, their application scope is limited by complex compositions and manufacturing processes, as well as single‐function. In this study, solid‐state reaction was utilized to prepare transparent‐ferroelectric (K0.5Na0.5)NbO3 (KNN) ceramics by simply codoping with Dy3+ and Sr2+, providing possibilities for large‐scale production. Ceramics exhibit high optical transmittance, high‐quality white‐light emission and relaxor ferroelectric feature. Under irradiation of UV light, photochromic behavior occurring in the ceramics, resulting in modulating the optical performances, especially quality of emitted white light. Multifunctionality can expand latent applications of KNN‐based ceramics from white light‐emitting diodes to modulated optoelectronic devices.