The time-dependent quantum wavepacket approach has proven to be a powerful computational approach for studying large scale quantum reactive scattering problems involving three or more atoms. This article presents an account of some recent development of time-dependent wavepacket methods for accurate quantum dynamics calculation of tetraatomic reactions in full dimensional space. The salient features of the time-dependent approach and important computational strategies that have been employed to successfully calculate state-specific reaction dynamics for realistic four-atom reactions are discussed. Some results from the application of the time-dependent methods to several specific reactions, in particular the benchmark H-2 + OH reaction, are presented. The article is then highlighted with the presentation of a general reactant-product decoupling method for state-to-state reactive scattering study. Finally, the future outlook of the theoretical study of polyatomic reaction dynamics is discussed.