The diaphragm valve uses a metal dish-type diaphragm set to control the inflow and outflow of fluid. The metal dish-type diaphragm set is above an air flow channel to control the stem above the metal dish-type diaphragm set, and the air will be blocked by pressing the metal dish-type diaphragm to make it fit the metal valve base in the air flow channel; this non-metal valve base is fixed in the air flow channel by a fixed shrunk ring with a taper cross section, and the in-between metal diaphragm in the metal dish-type diaphragm set is annular in the center to reduce the metallic friction between metal diaphragms, to increase application times and to lower the leakage rate of the diaphragm valve.