A system feature of the radio-frequency (RF) heating system for JT-60 is described. This system contains three units Lower Hybrid Range of Frequencies (LHRF) and one unit Ion Cyclotron Range of Frequencies (ICRF) heating systems. The LHRF heating system produces about 24 MW at 2 GHz of RF power using 24 high power klystrons and the ICRF heating system does 6 MW at 120 MHz of RF power using 8 high power tetrodes. Development of a high power klystron for the LHRF heating system and the coupling system for high power density of the transmission are performed for the construction of the RF heating system for JT-60. Japan Atomic Energy Research Institute (JAERI) has already constructed the RF heating system for JT-60 and is now performing the coupling test to JT-60 plasma.