Is the use of electronic tags, of picking law library. First implemented in the warehouse location, variety of corresponding to the tag. Library, library information system and passed on to the appropriate location tag, showing the location stored goods required the number of libraries, and sends out light and sound signals, indicates that the pickers completed homework. DPS makes picking people or spend time looking for location and check the goods, just check the picking quantity and therefore improve picking speed and accuracy at the same time, and reduce labor intensity. Multiple pick area can be set using the DPS in order to further improve picking speed.