Abstract: High efficiency is one of the essential requirements for modern space Traveling Wave Tube (TWT) development, and a single percentage point increase of overall efficiency is very significant to translate into potential revenue increases. The enhancement of overall efficiency was realized by optimizing the helix pitch profile of a TWT to maximize the collector efficiency. The maximum collector efficiency of a TWT normally conflicts with the basic beam-wave interaction efficiency. Such a conflict has been mitigated via setting the electronic efficiency higher than 25% as a constraint of the algorithm to ensure a high output power. The 3-D large signal Beam-Wave Interaction Simulator (BWIS) of MTSS, which was employed to calculate the output power and the energy distribution of the spent beam, was integrated with the Genetic algorithm. The detailed design of a Ku-band helix traveling wave was described and maximum collector efficiency of 89% with electronic efficiency of 26.9% was achieved from the simulation results.