Abstract: In order to produce new combined filter,DR2-5 filter combiner was modified,involving the following parts:1) the filter rod drum and cutting knife in filter rod cutting section;2) the transmission gears in filter plug transferring section;3) the transportation wheel and lifting sprocket wheel in filter plug insertion section;4) the spiral of collator drum in filter plug collating section.The modification of DR2-5 filter combiner realized the conversion of combined filter specification from 10 mm+10 mm to 15 mm+15 mm,and filter rod quality was in compliance with the related standard.The modification,which started from the end of the transmission system,had the benefits of minimum parts replacement,simple in retrofitting and commissioning,and cost saving.