Top-down proteomics is a revolutionary application for the identification and characterization of protein, known to be one of the most complicated and challenging issues in biology. In top-down proteomics, the quality and speed of the data warehouse is very important, as high accuracy results are returned by a database search.ProSight Warehouse fills the critical role as the data warehouse for ProSight PTM, the first publicly available top-down proteomics software suite.MySQL, a free relational database, was the base of this warehouse.Many annotated and predicted protein forms have been successfully incorporated into the organism-specific database and in the integrated database for human strains.To achieve high quality and efficiency, a database schema (Absolute Mass Search), data annotation methods (Shotgun and Extended Shotgun Annotation), data population strategies (on-the-fly population, bulk-loading method), and a database integration methodology for human protein were developed.With the successful implementation of ProSight Warehouse, ProSight PTM achieved its aspiration, highly accurate protein identification and characterization.