Magnetoplumbite-type LaMgAl11O19 ceramic has been proposed as one of promising candidates for the next generation thermal barrier coatings (TBCs) due to its low thermal conductivity. However, LaMgAl11O19 shows poor water-resistance with significant weight loss at elevated temperatures in water-containing atmosphere. In this work, we revealed that the essential reason for the poor water-resistance of magnetoplumbite-type LaMgAl11O19 ceramic is Mg2+ migration from the intrinsic site under moisture environment. And then an effective approach was proposed to improve its anti-deliquescent property by completely substituting divalent alkaline earth ions Mg2+ with Zn2+. Finally, a panoscopic strategy was proposed to further lower thermal conductivity through co-substituting La and Zn sites in LaZnAl11O19 with trivalent and divalent transition metal ions. The mechanism for the lowered thermal conductivity is due to the panoscopic approach, which providing all-scale hierarchical architectures of phonon scattering mechanisms. The excellent anti-moisture performance and ultralow thermal conductivity endow the LaZnAl11O19 based ceramics as a kind of promising candidates for advanced thermal barrier coatings.