Abstract: OBJECTIVE The application of lactose in dry powder inhalers (DPI) was reviewed and the ideas for research and development of DPI were provided. METHODS After looking up the related references published recently, home and abroad, the influenced of coarse carrier properties and added fine particles on pulmonary deposition of DPI were mainly summarized. RESULTS Aerosol performance of drugs in DPI is decreased after micronization. Research shows that the aerosol performance of drugs could be effectively improved by adding lactose, thereby the efficiency of drugs deposition in the lung is enhanced and the best potency is achieved. CONCLUSION The deposition of drugs in the lung could be effectively improved by adding coarse carrier with different properties and fine particles.