The formation mechanism of repulsive transition in underwater wet welding was first analyzed. Affected by the aqueous environment, the molten droplet during underwater welding is subjected to combined actions of multiple forces. The gas pressure, gas drag force, and plasma flow force acting on the droplet fluctuate dynamically due to the generation location of arc bubbles and the position of the cathode spot, which constitute the main driving forces for the repulsive transition of the droplet. The surface tension impedes lateral detachment of the droplet from the wire tip, while gravity facilitates droplet separation from the wire tip to complete the transition. The influence of pulse current frequency, duty cycle, and peak current on weld formation, droplet transfer, and welding stability in underwater wet welding was investigated using the orthogonal experimental method. The coefficient of variation of weld reinforcement was adopted to evaluate formation quality. The experimental results indicated that optimal welding performance was achieved when the duty cycle ranged between 15-20%, the peak current was 350 A, and the pulse frequency was approximately 20 Hz. By applying pulsed current during the peak current phase, the electromagnetic contraction force acting on the droplet was significantly enhanced, promoting droplet transfer and increasing the transition frequency.