• A burst mode high power laser system with arbitrary envelope of burst generation. • 0.2 mJ pre-shaped bursts with pulse peak power of 5.3 MW generated from the high power laser system. • The burst mode fiber laser system achieved 5.5 W second-harmonic output with a conversion efficiency of ∼ 41% • The 0.45 W UV burst has been achieved with a conversion efficiency of ∼ 12%, the wavelength of the UV burst can continuously tune from 259.7 nm to 261.2 nm. In this paper, we report a 100-kHz-rate femtosecond burst-mode high-power laser system with the capacity for arbitrary-envelope burst generation. After passing through a rod-type fiber amplifier, the energy of a single burst was found to reach 0.2 mJ at a 100-kHz burst rate with a pulse peak power of 5.3 mW. Using this system, we also achieved a 5.5-W second-harmonic output with a conversion efficiency of ∼ 41% and a spectral bandwidth of 4 nm. A 0.45-W ultraviolet (UV) burst was further obtained with a conversion efficiency of ∼ 12% and a spectral bandwidth of ∼ 0.4 nm, while the wavelength of the UV burst can be continuously tuned from 259.7 to 261.2 nm. [ABSTRACT FROM AUTHOR]