Anti‐counterfeiting techniques have become a global topic since they is correlated to the information and data safety, in which multimodal luminescence is one of the most desirable candidates for practical applications. However, it is a long‐standing challenge to actualize robust multimodal luminescence with high thermal stability and humid resistance. Conventionally, the multimodal luminescence is usually achieved by the combination of upconversion and downshifting luminescence, which only responds to the electromagnetic waves in a limited range. Herein, the Yb3+/Er3+/Bi3+ co‐doped Cs2Ag0.6Na0.4InCl6 perovskite material is reported as an efficient multimodal luminescence material. Beyond the excitation of ultraviolet light and near‐infrared laser (980 nm), this work extends multimodal luminescence to the excitation of X‐ray. Besides the flexible excitation sources, this material also shows the exceptional luminescence performance, in which the X‐ray detection limit reaches the level of nGy s−1, indicating a great potential for further application as a colorless pigment in the anti‐counterfeiting field. More importantly, the obtained double perovskite features high stability against both humidity and temperature up to 400 °C. This integrated multifunctional luminescent material provides a new directional solution for the development of multifunctional optical materials and devices. A Yb3+/Er3+/Bi3+ co‐doped Cs2Ag0.6Na0.4InCl6 double‐perovskite material shows multi‐modal luminescence under excitation by X‐rays, ultraviolet light, and near‐infrared laser light (980 nm), which also features high stability against humidity and high temperature (up to 400 °C). This luminescent material further extends the functionality and potential for future commercial applications in anti‐counterfeiting and X‐ray detection.