This paper reports the design, simulation work and test results of a 150W Ku-band continuous wave space Traveling Wave Tube (TWT), which is fulfilled at the Institute of Electronics, Chinese Academy of Sciences. The double-anode gun, helix pitch-tapering slow wave structure, non-axisymmetric four-stage depressed collector and radiation-cooled radiator are used in this TWT. The test results indicate that in the case of saturated drive, the TWT can get a power of more than 154W, an efficiency of more than 62%, a phase shift less than 46.6 degree, and AM/PM factor less than 4.3deg/dB with the beam transmission rate of more than 98.5% in the operation band of 12.25–12.75-GHz. The environment testing was performed and the results show that the configuration design of this TWT is satisfied for a satellite mechanics environment and the heat dissipation design is satisfied for an airborne environment.