Abstract: Triple-wire indirect arc welding is a new welding method. During the welding process, the workpiece is not connected to the power source, the main wire is connected to the positive electrode of the welding power source, and the two side wires are connected to the negative electrode of the two welding power sources respectively. The arc is established between the main wire and the two side wires. The melting of the welding wire leads to the change of the conductive distance between the main wire and the side wire, and the multiple droplet transfer paths formed by the welding wire which pose a challenge to establishing a stable welding process. In this paper, by adjusting the pulse frequency, the influence of pulse frequency on arc characteristics, droplet transfer path, welding voltage and welding current distribution is analyzed. The results show that the pulse frequency has a greater impact on the stability of triple-wire indirect arc welding. When the pulse frequency is greater than 100 Hz, a stable indirect arc can be established. As the pulse frequency increases, the droplet transfer path decreases, which is more conducive to forming a uniform weld bead. As the increase of pulse frequency, the variation coefficient of welding voltage and welding current decreases, the fluctuation degree of welding current and welding voltage decreases, and the stability of three-wire indirect arc welding improves.