One of the main reasons for the stability issue of inorganic perovskite quantum dots (PQDs) is the fragile protection of surface ligands. Here, an armor-like passivation strategy is proposed to improve the comprehensive stability of PQDs via a solvothermal fabrication method. That is, forming an armor-like protection layer for every single surface point by introducing coupling ligands with strong affinity (both L and X type ligands). The interactions between ligands via hydrogen bonds and strong affinity of ligands to surface atoms are evidenced by 1H-nuclear magnetic resonance measurements and Fourier transform infrared spectroscopy. As a result, long-term storage stability, high quantum yield, good water resistance, and good radiation hardness of PQDs are achieved. More than 60% of the radioluminescence intensity of the PQD film could be retained under continuous irradiation of 42 kGy. The output power can even be increased by 34.48% compared with the battery without PQD film. This armor-like passivation strategy also provides good reference for the stability improvement of both light-emitting and photovoltaic devices.