The present invention provides a filter for drinking water, including six filtering bottles. The fifth filtering bottle is formed with ion exchange resins, and the sixth filtering bottle is formed with a ceramic filtering core. The arrangement of the original third and fourth filtering bottles of the prior art is transposed, and a device for preventing a magnet of the filter from rusting is provided. The filtering bottles are orderly in turns and connected by tubes, and the fourth filtering bottle is connected with the fifth and sixth filtering bottles by a three-way pipe. Water is poured into a first filtering bottle and discharged from the fifth or sixth filtering bottle.