Dual-responsive (light and pH) yolk-shell structured drug delivery nanocapsules, each consisting of a movable upconversion nanoparticle (UCNP) core and a shrinkable poly(methacrylic acid) (PMAA) shell, were prepared by distillation precipitation polymerization. Mono dispersed NaYF4: Yb3+/Tm3+ UCNPs were synthesized and encapsulated in silica templates, followed by coating to form PMAA shells. Subsequently, the silica templates were dissolved to form nanocavities for drug loading. The PMAA shell contains pH and ultraviolet (UV) light sensing moieties, enabling a control release upon the exposure of nanocapsules to these stimuli. The near-infrared (NIR)-to-UV feature of UCNPs allows azobenzene isomerization to be light triggered remotely to control contraction and swelling of PMAA shells. The loading efficiency of the anticancer drug doxorubicin (DXR) was up to 17 wt % due to the unique nanoporous structure of PMAA shells. The values of the diffusion coefficient under different release conditions were determined using the Baker-Lonsdale model to facilitate the design of dual-responsive drug release devices or systems.