Abstract Dynamic responsive scintillating materials play a significant role in advanced radiation detection technology. However, the issues such as thermal quenching, uncontrollable structure, and unsatisfactory cost, still remain obstacles to the diversified development of recent scintillators. Herein, a strategy is proposed by assembling well‐designed inorganic and organic building units with low cost to construct a series of novel lanthanide MOFs for thermal‐adaptive X‐ray scintillators (TAXS). Based on the delicate energy level design, the as‐obtained TAXS present ultra‐high relative light yield (max ≈49 700 photons MeV −1 ), tunable luminescence (from green to red band), and low dose rate detection limit (min ≈118.7 nGy air s −1 ). Importantly, these TAXS exhibit unique thermal‐adaptive behaviors including thermal‐facilitated metal‐ligand distance contraction and X‐ray‐induced carrier generation, resulting in obvious enhanced radio‐luminescence. They maintain perfect linear response to X‐ray (R 2 > 99.8%) and excellent stability (>95% after 215 Gy air X‐ray irradiation) during heat treatment. Both TAXS‐based membranes with high imaging resolution (max ≈24 lp mm −1 ) and inks for customizable printing demonstrate the potential to work normally at elevated temperatures. Such a strategy supports photonic functional MOFs to fabricate high‐performance scintillators for harsh condition services.