A diaphragm pump with a heat dissipation mechanism includes a seat body, a diaphragm assembly, and a rotor pump assembly. The seat body includes a rotating member therein. The diaphragm assembly includes a piston mechanism and a diaphragm mechanism. The diaphragm assembly and the seat body confine a first pump room in which a medium is received. The rotor pump assembly is disposed between the rotating member and the diaphragm assembly. The rotor pump assembly includes a casing. The casing includes a suction port communicated with the first pump room and a discharge port communicated with the at least one medium outlet. The rotor pump assembly includes an outer rotor rotatably connected with the casing and an inner rotor rotatably connected with the outer rotor. The inner rotor is rotatably connected with the drive shaft. The outer rotor and the inner rotor rotate at different speeds.