We demonstrate a high power microsecond UV burst-mode laser system with a GHz-adjustable intra-burst pulse frequency. The laser system has a pulse energy of 152 mJ at 355 nm, corresponding to a peak power over 300kW. It’s pulse burst duration and repetition are 1.15 μs and 10 Hz, respectively. The intra-burst pulse frequency of the UV burst laser can be adjustable from 1 to 10 GHz with a sine waveform. To the best of our knowledge, this is the highest reported UV burst-mode laser for output energy and peak power with microsecond burst duration, and the widest tuning range of intra-burst frequency. The high-power microsecond UV burst-mode laser can be directly used as a light driven source in large bandwidth/high-power microwave photonic systems, providing a long pulse width and high peak power laser while significantly improving the system's multi-parameter adjustment capability and adaptabilit