Microchemical systems exhibit a unique capacity of preparing and manipulating various nanomaterials. In this review, the state-of-the-art microchemical systems and the on-demand development for the preparation of novel inorganic nanomaterials with certain dimensions or complex structures are summarized and discussed. Multistep synthesis and manipulation in microchemical systems are presented and compared, as well as new strategies such as in-line monitoring, feedback control, and self-optimization. The design and strategy for tuning the nucleation, growth, functionalization, and assembly of nanomaterials are considered. The challenges are put forward and an outlook for the future directions of nanomaterial preparation and production in microchemical systems is specially provided.