Abstract: To satisfy the requirements of the high-power microwave system on flexible targets, multi-targets and group target scenes for jamming and damage, for the first time in domestic, a helical phased array system, which involves particle swarm optimization to realize various beampattern synthesis, and a servo motor control system to enable the helical elements to rotate to the appointed positions, are designed, fabricated and measured in this papaer. The proposed antenna array can realize accurate beam scanning within ±20° by electrically controlling the rotation of its helical elements. The realized gain of the high-power microwave helical array is 30.7 dBic, 29.2 dBic and 26 dBic when the beam is not deflected, deflected by 10° and deflected by 20°, respectively. A beam broadening with a 6 dB beamwidth of 31.1° (-15.6°~15.5°) and double beam pointing of -14.1° (22.5 dBic) and 14.3° (23.3 dBic) are realized, while the measured results are in good agreement with the simulation ones. Circular polarization characteristics are achieved at corresponding angles in the beam forming, 2D scanning and broadening experiments except for double beam deflection application, where the circular polarization characteristics deteriorate notably and its axial ratios are over 3 dB at corresponding angles. Based on the measured beampattern synthesis results, theoretical calculation and contrastive analysis are conducted on the damage ability of the high-power microwave system under different beampattern control application conditions. The proposed prototype with multiple pattern synthesis strategies greatly improves the beam flexibility of the high-power microwave system and has an essential application value in the group targets and discrete targets damage.