Dai's research activities are mainly concentrated in two fields:  to develop computational methods for the strongly correlated materials, and to search for the topological non-trivial quantum state in realistic materials. In the first field, he develops the Gutzwiller density functional theory (LDA+Gutzwiller) and applies it to study many of the correlated materials, i.e. ferromagnetic metals, iron based superconductors and topological Kondo insulators. In the second field, he proposes several very important topological insulators, i.e. Bi2Se3, Bi2Te3 and Sb2Te3. His group predicted the quantum anomalous Hall effect in the magnetic topological insulator thin films, which was observed in 2013. In 2015, his research team predicted the Wely semimetal materials TaAs family, which was later confirmed by both photo emission and transport experiments.