Using high-speed photography and synchronized electrical parameter measurements, we investigated the repetitive discharge evolution characteristics of rod-rod electrode structures in water. The research revealed that the discharge process divides into three typical stages: liquid phase disturbance development, bubble colony evolution, and breakdown with bubble pulsation. Liquid phase disturbances expand toward the gap center under electric field and Joule heating effects; micro-bubbles form, expand, and then collapse into bubble colonies; discharge preferentially occurs inside bubbles, and after breakdown, bubbles exhibit "expansion-collapse-re-expansion" pulsation characteristics. Experiments show that discharge voltage (4-8kV), pulse width (2-12μs), and pulse frequency (20-2000Hz) all correlate negatively with the evolution rate of gap equivalent resistance and repetitive pulse withstand times. Higher discharge voltage accelerates liquid phase disturbance expansion; increased pulse width extends energy injection time and promotes bubble generation in the disturbed phase; high-frequency conditions promote heat and micro-bubble accumulation in the gap and accelerate the breakdown process, while low-frequency conditions inhibit cumulative effects due to complete recovery of the water medium.