This dissertation describes the development of polymer ligation for inorganic nanoparticle surface modification and stabilization. In chapter 1, synthetic strategies for inorganic nanoparticle-polymer interface construction are summarized, with an introduction of physicochemical effects from the incorporated polymers. The following chapters give the detailed in-depth discovery of the polymer-inorganic hybrid nanoparticles. In Chapter 2, surface-initiated polymerization was used for stabilizing and passivating the perovskite nanocrystals in harsh conditions. The produced perovskite-polymer nanocomplex demonstrated composition-dependent structural stability and colloidal dispersity. Meanwhile, the polymer ligands on perovskite nanocrystals provided possibilities to regulate the halide exchange reactions, and the details were discussed in Chapter 3. Chapter 4 explored the application of perovskite-polymer nanocomplex in photocatalytic organic transformations, during which the polymers stabilized the perovskite surface and enabled the easy separation of perovskite-polymer nanocomplex from the reaction media for repeated use. Chapter 5 presents the synthesis of a polymer-modified magnetic nanoplatform for selective protein immobilization, which was prepared from surface-initiated atom transfer radical polymerization. The surface-tethered polymers provided abundant sites for the target protein immobilization while enabling the excellent colloidal stability of the magnetic nanoparticles in the meantime. The applications of prepared magnetic nanoparticles in protein separation and water treatment were described in detail in the following Chapter 6.