Dry powder inhalers (DPIs) have the characteristics of non-invasiveness, eliminating gastrointestinal malabsorption and avoiding first-pass effects, and are widely used in the treatment of respiratory diseases. In recent years, with the broadening of indications and the expansion of medicaments based on treatment with DPIs, more innovative patents have emerged. Therefore, a comprehensive review of DPI patents from different key technical perspectives is of great importance. In this review, we analyzed the disease indications, medicaments, milestone patents, and small molecule inhibitors of DPI based on comprehensive retrieval of global patents from the Derwent Innovation platform, which covered 12,916 patent documents published before December 31, 2020. This study further identified the currently popular technologies in the DPI field and explores the most likely emerging development directions to support researchers in making relevant R&D decisions.